odontogenic cysts

Odontogenic cysts

1. Odontogenic Cysts SEMINAR PRESENTED BY P.PRAVEEN 2 ND YEAR PG

2. DEFINITION Kramer (1974) has defined a cyst as ‘a pathological cavity having fluid, semifluid or gaseous contents and which is not created by the accumulation of pus ; frequently, but not always, is lined by epithelium. By Killey and Key 1966 described as epithelium lined sac filled with fluid or semisolid material.

3. Most cysts, but not all, are lined by epithelium. Cysts of the oral and maxillofacial tissues that are not lined by epithelium are The mucous extravasation cyst of the salivary glands The aneurysmal bone cyst Solitary bone cyst

4. CLASSIFICATION (shear) I Cysts of the jaws A Epithelial-lined cysts 1 Developmental origin (a) Odontogenic Gingival cyst of infants Odontogenic keratocyst Dentigerous cyst Eruption cyst Gingival cyst of adults Developmental lateral periodontal cyst vii. Botryoid odontogenic cyst viii. Glandular odontogenic cyst ix. Calcifying odontogenic cyst (b) Non- odontogenic i . Midpalatal raphé cyst of infants ii. Nasopalatine duct cyst iii. Nasolabial cyst 2 Inflammatory origin i . Radicular cyst, apical and lateral ii. Residual cyst iii. Paradental cyst and juvenile paradental cyst iv. Inflammatory collateral cyst

5. B Non-epithelial-lined cysts 1 Solitary bone cyst 2 Aneurysmal bone cyst II Cysts associated with the maxillary antrum 1 Mucocele 2 Retention cyst 3 Pseudocyst 4 Postoperative maxillary cyst

6. III Cysts of the soft tissues of the mouth, face and neck 1) Dermoid and epidermoid cysts 2) Lymphoepithelial ( branchial ) cyst 3 ) Thyroglossal duct cyst 4) Anterior median lingual cyst ( intralingual cyst of foregutorigin ) 5 )Oral cysts with gastric or intestinal epithelium (oral alimentary tract cyst) 6) Cystic hygroma 7) Nasopharyngeal cyst 8) Thymic cyst 9) Cysts of the salivary glands: mucous extravasation cyst; mucous retention cyst; ranula ; polycystic ( dysgenetic ) disease of the parotid 10) Parasitic cysts: Hydatid cyst Cysticercus cellulosae T richinosis

7. (WHO) Classification of cysts of jaws A. EPITHELIAL-LINED CYSTS 1 Developmental Origin (a) Odontogenic Developmental Odontogenic keratocyst Dentigerous Developmental lateral periodontal cyst Calcifying odontogenic cyst 2 INFLAMMATORY ORIGIN Radicular cyst, apical and lateral Residual cyst b) Non- odontogenic Midpalatal raphe cyst of infants Nasopalatine duct cyst B. NON-EPITHELIAL-LINED CYSTS Solitary bone cyst Aneurysmal bone cyst Cyst of maxillary antrum Surgical ciliated cysts of maxilla Benign mucosal cyst of the maxillary antrum

8. A.SOFT TISSUE CYSTS ODONTOGENIC Gingival cysts Adulits Newborn B.NON ODONTOGENIC Anterior median lingual cyst Nasolabial cyst C.RETENTION CYST SALIVARY GLAND CYSTS Mucocele Ranula D.DEVELOPMENTAL CYST Dermoid & epidermoid Lymphoepithelial cyst Thyroglossal cyst Cystic hygroma E.PARASITIC CYSTS Hydatid cyst Cysticercocis F.HETEROTROPIC CYSTS Oral cyst with gastric or intestinal epithelium

9. The dentigerous cyst is defined as a cyst that originates by the separation of the follicle from around the crown of an unerupted tooth The dentigerous cyst encloses the crown of an unerupted tooth and is attached to the tooth at the cementoenamel junction The pathogenesis of this cyst is uncertain, but apparently it develops by accumulation of fluid between the reduced enamel epithelium and the tooth crown . DENTIGEROUS CYST (FOLLICULAR CYST OR PERICORONAL CYST)  

10. Gross specimen of a dentigerous cyst. Cyst encloses the crown of the tooth and is attached to its neck Dentigerous cyst

11. Experimental studies on bone resorption There is evidence that vital cyst tissue in culture releases a potent bone resorbing factor that is predominantly a mixture of prostaglandins (PGE2) and E3. Data proposed by Harris indicated a lower levels of PGE2 released by dentigerous cysts 12.2+/ 9.4ng/mg than the radicular 16.6+/- 13ng/mg or by OKCs 20 +/-11ng/mg. PGE2 is one of the factor responsible for osteolytic effects

12. Interleukin 1 (IL1 ) may be produced by odontogenic cysts and may account for raised levels of prostaglandin and collagenase synthesis by the cyst capsules. IL1 released by the cysts leads to stimulation of osteoclasts to resorb bone and the connective tissue cells to produce prostaglandins that will be responsible for further osteoclast activation. It also stimulates connective tissue cells to produce collagenase which is involved in the destruction of bone matrix

13. Glycosaminoglycans , predominantly hyaluronic acid but also appreciable amounts of heparin and chrondrotoin sulphate are present in the fluids and walls of dentigerous cyst. Release of glycosaminoglycans from the walls and their diffusion in to the cyst fluid is thought to have an important role in expansive cyst growth by increasing the osmolality of the cyst fluid and hence raising the internal hydrostatic pressure of cyst

14. Clinical features Develop around the crown of unerupted or supernumerary tooth. Most commonly occur in the second and third decades M ale to female ratio of 2:1. Examination reveals a missing teeth or tooth with hard swelling Occasionally resulting in facial asymmetry.

15. Sites – Mandibular and Maxillary third molars, Maxillary canines. According to Gilibisco cyst is most often in decreasing order like third molars, canines, second premolars. Bilateral or multiple cysts can occur in association with number of syndromes including cleidocranial dysplasia and Maroteaux Lamy syndrome. Expansion of cortical plates due to pressure extension may be seen.

16. Clear, pale straw colour fluid Cholesterol crystals. Total protein in excess 4 g / 100ml. On aspiration

17. Radiographic features Classically consists of a well corticated pericoronal radiolucency which exceeds 5mm when measured from edge of crown to periphery of lesion on radiographs

18. CENTRAL TYPE: LATERAL TYPE : CIRCUMFERENTIAL TYPE : RADIOLOGICAL FEATURES

19. Location : Dentigerous cyst if found just above the crown of the involved tooth, which usually is the mandibular or maxillary third molar or the maxillary canines. Cyst attaches to the c ementoenamel junction. Cysts related to maxillary third molar may often grow in to the sinus and may become quite large before they are discovered. Cyst attached to the crown of mandibular molars may extend a considerable distance in to the ramus

20. Periphery and shape : Well defined cortex with a curved or circular outline. If infection is present the cortex may be missing. Internal structure: Internal aspect is completely radiolucent except for the crown of the involved tooth

21. Effects on surrounding structures: Cyst has a potential to displace or resorb adjacent teeth. Commonly displaces the associated tooth in a pical direction. In case of maxillary third molars and cuspids they may be pushed to the floor of orbit and in mandibular third molars they may be pushed to the condylar or coronoid region or to the inferior border of mandible. Floor of maxillary antrum may be displaced as the cyst invaginates the antrum In case of lower it may displace the inferior alveolar canal in inferior direction Expands the outer cortical boundary of the involved jaws

22. Axial contrast - enhanced CT image obtained with soft-tissue window settings Black arrowheads => cystic with enhancing soft-tissue septations white arrowheads=> mural nodules Arrow=> Cortical disruption at the posterolateral aspect of the mass Axial unenhanced CT image obtained with bone window settings shows Black arrow => unerupted wisdom tooth centered in the cystic expansile mass white arrow=> cortical breakthrough of the posterolateral aspect of the mass is seen

23. Sagittal contrast-enhanced reformatted CT image shows : The overall size of the mass and its cystic and solid components Black arrowas => Unerupted tooth . Arrowheads => Septations . white arrow => Large mural nodule. Ceylan Z. Cankurtaran , MD et al Ameloblastoma and Dentigerous Cyst Associated with Impacted Mandibular Third Molar Tooth 1 ;2010

24. HISTOLOGICAL FEATURES Composed of connective tissue wall with a thin layer of stratified squamous epithelium lining the lumen. connective tissue wall is frequently thickened and composed of a very loose fibrous connective tissue Inflammatory cells commonly infiltrate the connective tissue. Shows rushton bodies with in the lining epithelium. Content of cystic lumen is usually thin, watery yellow and is occasionally blood tinged.

25. cyst markers in dentigerous cyst Amelogenin is a lowmolecularweight enamel matrix protein. Dentigerous cysts show positive expression for amelogenin The expression of amelogenin is possibly an indicator of differentiation of epithelial cells in the odontogenic lesions amelogenin showing an intense well defined linear pattern Natl J Maxillofac Surg. 2014 Jul-Dec; 5(2): 172–179

26. Dentigerous cyst with high expression of P63 in almost all epithelial layers. P63 : ( Baretto et al (2002) Positive expression for PTCH gene was demonstrated in the epithelium of the dentigerous cysts.

27. Calcifying odontogenic cysts Adenomatoid odontogenic tumors Cystic ameloblastoma Ameloblastic fibroma Odontogenic keratocyst Radicular cyst of primary tooth Hyperplastic follicle Differential diagnosis

28. TREATMENT Small cysts are surgically removed which may include tooth . Large cysts may be treated by marsupialization before removal. Potential complications of dentigerous cyst Ameloblasoma Squamous cell carcinoma Mucoepideroid

29. ERUPTION CYST Odontogenic cyst with the histologic features of dentigerous cyst that surrounds tooth crown that has erupted through the bone but not soft tissue. Occur when the teeth is impeded in its eruption within the soft tissue. Eruption cyst represents less than 1% of odontogenic cysts (Shear 1992).

30. Clinical features Soft fluctuant dome shaped bluish swelling on the alveolar ridge. Most commonly found in children and adults if there is a delayed eruption. Deciduous and permanent tooth may be involved most frequently anterior to first permanent molars. Usually painless unless infected.

31. Radiographic features Show soft tissue shadow since it is confined with in it and there is usually no bony involvement. Treatment No treatment is necessary as the cyst often ruptures by itself. Surgical exposure of tooth crown may lead to eruption process

32. LATERAL PERIODONTAL CYST Intra osseous cyst which occurs on the root surface of a vital teeth. Condition is unicystic but may appear as a cluster of small cysts, a condition referred to as “ Botryoid odontogenic cyst”. It is now widely accepted that the term lateral periodontal cyst should be confined to cysts in the lateral periodontal position in which an inflammatory etiology and a diagnosis of gingival cyst of the adult and collateral keratocyst have been excluded on clinical and histochemical grounds. (Shear and Pindborg ,1975: Wysocki et al 1980,Cohen et al 1984: Altini and Shear ,1992)

33. Variant of lateral periodontal cyst is Botyroid odontogenic cyst which was described by Weather and Waldron in 1973 for the multilocular radiographic appearance of lateral periodontal cyst Clinical features Sex: More common in males. Age: occurs particularly between the 5th to 7th decades. with an average of 54 years. Clinically it presents no signs or symptoms but occasionally a small swelling of the gingiva or alveolar mucosa. Asymptomatic and are less than 1 cm in diameter. Detected during radiographic examination.

34. Radiographic features Location 50-75% of lateral periodontal cysts develop in mandible,mostly in the region of lateral incisor to premolar. Occasionally in maxilla they develop in cuspid and lateral incisor region. Periphery and shape Well defined radiolucency with a corticated border. Round or oval in shape. Rarely large cyst may have irregular outline. If the cyst becomes secondarily infected it mimics lateral periodontal abscess.

35. Radiograph of a lateral periodontal cyst lying between the mandibular premolar teeth. The margins are well corticated, indicative of slow enlargement.

36. Internal structure : Totally radiolucent. Botyroid variety may show multilocular appearance. Effects on surrounding structure : Small cyst may efface the lamina dura of adjacent teeth Large cyst may displace the adjacent teeth. Differential diagnosis : Lateral radicular cyst Mental foramen Small OKCS Lateral periodontal abcess

37. The lateral periodontal cysts are lined by a thin, non- keratinising layer of squamous or cuboidal epithelium usually ranging from 1 to 5 cell layers wide, which resembled the reduced enamel epithelium . The epithelial cells were sometimes separated by intercellular fluid. Their nuclei were small and pyknotic . Small epithelial nests may be seen in connective tissue wall, which may show signs of mild inflammation . HISTOLOGICAL FEATURES

38. Lateral periodontal cyst which in part has a thin, nonkeratinised stratified squamous epithelial lining resembling reduced enamel epithelium. Two epithelial plaques are seen. The one on the right is convoluted

39. Areas of separation of the epithelium from the underlying connective tissue is a frequent finding. Histological appearance of the lesion, occasional clear cells in basal layer Connective tissue adjacent to the epithelim exhibits zone of hyalinization Treatment Excicional biposy or simple enucleation with no tendency toward recurrence .

40. Diagram illustrating the possible mode of formation of epithelial plaques by localised proliferation of cells. (a) Cyst lined by thin epithelium resembling reduced enamel epithelium. (b) Early epithelial thickening by basal cell proliferation. (c) Basal cells continue to proliferate. Superficial cells swell by accumulation of intracellular fluid. (d) and (e) Basal proliferation ceases or slows down. Superficial cells are waterlogged and swollen. Plaque protrudes into cyst cavity and cyst wall where it can undermine and raise adjacent cyst lining. (f) Epithelial plaque can form convolutions. Protrusions into cyst wall as in (c–f) may be ‘pinched off’ and develop into daughter cysts, leading to the formation of the botryoid variety of lateral periodontal cyst.

41. ODONTOCYSTGENIC KERATOCYST There had been a great deal of interest in the odontogenic keratocyst since it became apparent that it may grow to large size before it manifests clinically and that unlike other jaw cysts It has a particular tendency to recur following surgical treatment The term ‘ odontogenic keratocyst ’ was introduced by Philipsen (1956). Shear used the term ‘ keratocystoma ’ (2003). It is termed as ‘ keratinising cystic odontogenic tumor’ by Richart and Philispen (2004). In 2005 Philipsen proposed the term “ keratocystic odontogenic tumor”.

42. Etiology In the past OKC - originate from the primordium of a tooth before mineralization. Later on OKC thought to - Arise from Remnants of dental lamina. Basal cell layer of oral mucosal epithelium Stellate reticulum of the enamel organ. According to Stoelinga and Bronkhorst and Stoelinga and Peters OKCS may arise from proliferations of basal cells of oral mucosa.

43. Evidence of genetic factors in the etiology of sporadic keratocysts There is a gp 38 altered gene expression in keratocysts Increased expression of P53 protein in keratocysts noted. Tumor suppressor genes are expressed more strongly in OKCS than in other cysts. JOPM 2009( 38) 99-103

44.   Clinical features Occur in wide range Age distribution is bimodal with a peak in the second and third decades of life followed by another peak in the fifth decade of life or later. Sex: Males are commonly affected than females. Symptoms: OKCS usually have no symptoms . Although mild pain and swelling may occur. Discharge may be present.

45. Parasthesia of lower lip or teeth Some are unaware of the lesion until they develop pathologic fractures Patients are remarkably free of symptoms until they reached a large size Involving the maxillary sinus and the entire ascending ramus , including the condylar and coronoid processes. Occurs because the okc tends to extend in the medullary cavity and clinically observable expansion of the bone occurs late.

46. Voorsmit described the occurrence of large okc involving the maxillary sinus that led to displacment and destruction of the floor of thr orbit and proptosis of the eyeballs. Patride and towers reported a case extended from maxilla and eventually involved the base of the skull behaving rather like a low grade squamous cell carcinoma Parakeratinised oks have a substantially high recurrence than orthokeratinised okc Dayan et al have described the occurrence of a lesion entirely with in the gingiva , had the clinical features of a gingival cyst of adults but the histological characteristics of a typical okc . They have suggested the term peripheral odontoenic keratocyst

47. Gorlin and Goltz syndrome Syndrome was first described by Binkley and Johnson in 1951. Also called as :- -Nevoid-basal cell carcinoma syndrome -Bifid rib syndrome. Gorlin and Goltz found relationship between this syndrome and multiple odontogenic cyst. Hereditary autosomal dominant trait with high penetrance and variable expressively. Caused by mutation in patched(PCTH), tumor suppressor gene that has mapped to chromosome 9q 22.3

48. NBCCSyndrome composed of Multiple odontogenic keratocysts . Bifid ribs. Frontal bossing. Multiple nevoid basal cell carcinomas Therefore in any case of multiple unerupted teeth, a panaromic X ray must be taken to rule out this syndrome.

49. Frontal bossing Bifid rib

50. Site: OKCS develop more in mandible than maxilla. In mandible majority of cases of develop in ramus and third molar area and then anterior mandible. In maxilla, the most common area is third molar area followed by cuspid area. About half of all okcs occur at the angle of the mandible extending for varying distances into the ascending ramus and forward in to the body.

51. Woogler et al reported a high frequency in the mandibular molar ramus area (60%) of cysts unassociated with the syndrome than those with (44%). Where as more syndrome (21%)than non syndrome cysts(11%)occurred in the maxillary molar region.

52. POSIBLE REASONS FOR RECURRENCES : Occurrence of satellite cysts which may be retained during an enucleation procedures If enucleation procedures are incomplete New cysts arising from retained satellite microcysts or retained mural cell islands Okc linings are very thin and fragile particularly when the cysts are large and are there fore more difficult to enucleate than cyst with thick walls Portions of the lining may be left behind and constitute the origin of a recurrence(Kramer1963) Enucleation in one piece may be more difficult with cysts that have scalloped margins and this may explain the higher recurrence rate than with those with a smoother contour

53. multilocular , multicystic KCOT of the right mandible not associated with a missing tooth. The complexity of the lesion contributes to difficulty in total removal.

54. Voorsmit et al 1981 belived that a reccurrent okc may develop in three different ways - By incomplete removal of original cyst lining By the retention of daughter cysts From micro cysts or epithelial islands in the wall of the original cyst

55. Radiographic features Location: They may appear radiologically as small round and ovoid radiolucent areas. They may be well demarkated with distinct sclerotic margins . Many of these are unilocular radiolucencies with a smooth periphery. Some of the uniloular lesions have scalloped margins these may be misinterprited as multilocular radiolucencies . The multilocular variety is particularly liable to be misdiagnosed as ameloblastoma . The unilocular and multilocular lesions may involve the body and ascending ramus of the mandible extensively. Displacement of the inferior alveolar canal and resorption of the cortical plates Downward displacement of the inferior alveolar canal and resorption of the lingual cortical plate of the mandible may be seen as will as perforation of bone(smith and shear)

56. They may occur in the periapical region of the vital standing teeth giving the appearance of a radicular cyst . They may impede the eruption of a related teeth resulting in a dentigerous appearance radiologically “Main “ ( 1970 )has referred the variety of okc that embraces an adjacent unerupted tooth as envelopmental . Those that formed in place of normal tooth series called as replacement variety Those in the ascending ramus are away from the teeth as extraneous Those adjacent to the roots of teeth as collateral

57. Radiograph of a small odontogenic keratocyst

58. Radiograph of an odontogenic keratocyst with scalloped margins .

59. Radiograph of a multilocular odontogenic keratocyst .

60. CT : Ct scan in case of diagnosis of okc of large mandible and cysts and tumors of maxlla particularly where extension of the lesion to the cranial base is suspected .( Voorsmit ) Important features of this technique :- Lack of image superimposition Preservation of soft tisuue detail Selective enlargement of area of interest High degree of accuracy and possibility of three dimentional interpretation.

61. Odontogenic keratocyst (axial CT scan). Note marked expansion of the maxilla posteriorly by a cystic mass, however, the sinus itself is compressed anteriorly (arrows point to expanding posterior maxilla).

62. CT axial (a) and sagittal (b) images demonstrate the lingual and buccal cortical expansion and erosion Dentomaxillofacial Radiology (2011) 40, 133–140 ’ 2011 The British Institute of Radiology

63. 3D CT frontal (a) sagittal (b) images demonstrate the lingual, buccal cortical and basis of mandibular erosion with a multilocular bony defect like soup bubble appearance.

64. MRI: The MRI finding of KCOTs is described as uniformly thin walls with weak enhancement and fluids of heterogenous signal intensity. The contents of the cysts frequently showed intermediate or high T1- weighted signal intensity or intermediate T2-weighted signal intensity. In multilocular and large lesions T-1 weighted MR image showed the lesion with thick, strongly enhanced walls of uniform thickness And heterogeneous fluid contents in T-2 weighted MR image.

65. MR images demonstrate the low signal intensity on T1-weighted axial (a) and sagittal (b) images Nurhan G¨uler etal ConservativeManagement of Keratocystic Odontogenic Tumors of Jaws ; 2011

66. High signal intensity on T2-weighted sagittal images

67. ENLARGEMENT Rate of growth: In a number of studies pointed that inflammatory exudates had a negligible role in the enlargement of OKCs. As OKCS are intended to extend along the cancellous componenent of the mandible without producing much expansion of cortical plates, they frequently reached a large size before they were diagnosed. Although Browne was of opinion that these cysts grew more rapidly than other jaw cysts. Tollers view was that they grew at a similar rate to other epithelial cysts of jaw.

68. Toller suggested that majority of OKCS take about 6 years to recur to a clinically significant size of more than 1 cm diameter but with a wide time range, varying from 1 to 25 years. Forssell estimated that the rate of growth of OKCS varied from 2-14 mm a year, with a average of about 7mm and the rate was slow in patients over 50 years.

69. Role of osmolality in growth of the cysts Toller considered the part played the osmolality of the cyst fluid in the enlargement of OKCs. He showed that there was statistically significant difference between the mean osmolality of the OKCs compared with the mean serum osmolality . He suggested that osmotic differences between sera and cyst fluids were not directly related to proteins in cyst fluids and may be the result of the liberation of the products of cell lysis which may not be proteins. Main on the other hand, felt that mural growth in the form of epithelial proliferation was the essential process involved in the enlargement of OKCs

70. Role of inflammatory exudates in growth of the cysts Inflammatory exudate has a negligible role in OKC enlargement. Its cavity fluid contains low quantities of soluble protein, composed predominantly of albumin and only relatively small quantities of immunoglobulins . Role of glycosaminoglycans in growth of the cysts Smith et al reported on the presence and role of glycosaminoglycans in odontogenic cysts, including OKCs. Heparin sulphate showed a higher frequency and abundance in the OKCs than the other cysts.

71. Dirty, creamy white viscoid suspension Para keratinized squames. Total protein less than 4 g /100ml. Mostly albumin On aspiration

72. HISTOLOGICAL FEATURES : The epithelial lining is composed of a uniform layer of stratified squamous epithelium,usually six to eight cells in thickness. The epithelium and connective tissue interface is usually flat, and rete ridge formation is inconspicuous. The basal cell layer has columnar / cuboidal cells with reversely polarized nuclei, imparting a “picket fence” or “tombstone” appearance. The luminal surface shows flattened parakeratotic epithelial cells, which exhibit a wavy or corrugated appearance. Small satellite cysts, cords, or islands of odontogenic epithelium may be seen within the fibrous wall .

73. Epithelial lining is 6 to 8 cells thick, with a hyperchromatic and palisaded basal cell layer. Note the corrugated parakeratotic surface. OKC

74. TUMOR MARKERS IN KCOT KCOT was previously grouped under odontogenic cystic lesions with two histological Considering the biological behavior and genetic abnormalities. WHO working group 2005 grouped parakeratinized OKC as a benign neoplasm and orthokeratinised variant as a separate entity orthokeratinised odontogenic cyst (OOC). KCOT is an important neoplasm because of its high recurrence rate and aggressive behaviour. Oral Maxillofacial Surg Clin N Am 25 (2013) 21–30

75. Markers KCOT OOC Significance EMA, CEA   (Cell surface carbohydrates) Present in the surface parakeratin layer Absent Increased aggressiveness of KCOT CK 10, CK 13  (CK 10: Early marker of keratin differentiation)  (CK 13: Expressed in dental lamina, enamel organ, non-keratinized stratified squamous epithelium) In upper and surface parakeratin layers All the layers of the epithelium except basal layer. Related to epithelial cell maturation and proliferation.  OOC presents a well formed cystic envelope whereas the KCOT profile is compatible with more aggressive biologic behaviour  Ki-67 (Proliferative marker)  Intense expression Low expression Higher proliferative potential of KCOT IPO-38 (Proliferative marker) Intense expression Low expression Higher proliferative potential of KCOT gp38  ( Cell surface glycoprotein ) In basal and parabasal layers Negative Neoplastic potential of KCOT  Podoplanin   Intense expression Low expression Neoplastic potential of KCOT (EMA - Epithelial membrane antigen, CEA – Carcinoembryonic antigen, CK- cytokeratin , IPO - monoclonal antibody of IPO (Institute of Problems of Oncology, Kiev) directed against the nuclear antigen of proliferative cells,gp 38 – 38 kDa cell surface glycoprotein)

76. P63 is highly expressed as brown nuclei in OKC throughout the epithelial lining except parakeratinized layer POKC. Positivity to calretinin of the intermediate and parabasal layers, with negativity of the basal layers. Rare positivity of the stromal cells Matrix metalloproteinase (MMP) 2 and 9 shows positive expression for kcot .

77. DIFFERENTIAL DIAGNOSIS In case of unilocular Radiolucencies – Dentigerous cyst. Eruption cyst. COC. AOT. Unicystic ameloblastoma etc. In case of multilocular Radiolucencies – Conventional ameloblastoma CEOT Central giant cell granuloma , Aneurysmal bone cyst etc.

78. Treatments are generally classified as Conservative Aggressive Simple enucleation , with or without curettage Marsupialization Peripheral ostectomy . Chemical Curettage with Carnoy’s solution . Cryotherapy . Electrocautery and resection . Walid Ahmed Abdullah Surgical treatment of keratocystic odontogenic tumour: A review article 2011 MANAGEMENT :

79. Partsch I procedure (Decompression and marsupialization ) Decompression :- Technique that relieves the pressure within the cyst by making a small opening in the cyst and keeping it open with a drain. The marsupialization technique:- IT was described by Pogrel (2005) A window at least 1 cm in diameter is made into a cyst, and an attempt is made to suture the cyst lining to the oral mucosa. In the maxilla, the cyst is then often packed open with the packing protruding through the opening. The packing consists of iodoform gauze impregnated with bacitracin ointment.

80. Amount of tissue injury : Proximity of a cyst to vital structures can mean unnecessary sacrifice of tissue if enucleation is used. Surgical access : If access to all portions of the cyst is difficult, portions of the cystic wall may be left behind, which could result in recurrence. Assistance in eruption of teeth : If an unerupted tooth that is needed in the dental arch is involved with the cyst (i.e., a dentigerous cyst), marsupialization may allow its continued eruption into the oral cavity Extent of surgery : Marsupialization is a reasonable alternative to enucleation , because it is simple and may be less stressful for the patient Size of cyst : In very large cysts, a risk of jaw fracture during enucleation is possible. It may be better to marsupialize the cyst and defer enucleation until after considerable bone fill has occurred. Indication

81. Advantages : It is a simple procedure to perform. Marsupiaiization also spare vital structures from damage should immediate enucleation be attempted. Disadvantages : Pathologic tissue is left in situ, without thorough histologic examination. Patient is inconvenienced in several respects The cystic cavity must be kept clean to prevent infection, because the cavity frequently traps food debris. In most instances this means that the patient must irrigate the cavity several times every day with a syringe Marsupiaiization

82. 1) Anaesthesia 2) Aspiration 3) Incision Circular oval or elliptic. Inverted U shaped incision with broad base to the buccal sulcus . Mucoperioteum is reflected in this case. 4) Removal of bone 5) Removal of cystic lining specimen 6) Visual examination of residual cystic lining 7) Irrigation of cystic cavity 8) Suturing Cystic lining sutured with the edge of oral mucosa. In U shaped incision the mucoperiosteal flap can be turned into cystic cavity covering the margin. The remaining is sutured to oral mucosa. Technique of Marsupiaiization

83. 9) Packing-- Prevents food contamination & covers wound margins. Done with ribbon gauze soaked with WHITEHEAD VARNISH. COMPOSTION: Benzoin -10g Iodoform - 10g Storax -7.5g Balsam of Tolu - 5g Solvent ether to 100ml Pack changed for every 2 days. 10) Maintenance of cystic cavity Instruct the patient to clean and irrigate the cavity regularly with oral antiseptic rinse with a disposable syringe.

84. 11) Use of plug Prevents contamination. Preserves patency of cyst orifice. Plug should be stable, retentive and safe design. Should be made of resilient material ( avoid irritation) like acrylic. 12) Healing Cavity may or may not obliterate totally. Depression remains in the alveolar process.

85. A large, multilocular KCOT of the mandible on initial presentation. The same lesion 9 months later after biopsy, to establish the diagnosis insertion of 2 drainage tubes (seen on the radiograph) for decompression. The patient irrigated the drains twice daily with normal saline. The drains were removed after 1 year

86. Waldron’s method(1941) Two stage technique Combination of two standard technique First marsupialization Second enucleation,when the cavity becomes smaller Modifications of marsupialization

87. Indications When bone has covered the adjacent vital structures Adequate bone fill has strengthened the jaw to prevent fracture during enucleation Pt. finds difficult to clean cavity For detection of any occult pathologic condition Advantages Development of a thickened cystic lining which makes enucleation easier Spares adjacent vital structures Combined approach reduces morbidity Accelerated healing process Allows histopathological examination of residual tissue Disadvantages Patient has to undergo secondary surgery and possible complications

88. Cyst that have destroyed a large portion of of the maxilla and have ancroached on the antrum or nasal cavity Technique Anaesthesia Incision – gingival curvilinear incision taken along the involving teeth Two releasing incision are made at 45°angle and extending in to buccal sulcus Mucoperiosteal flap is raised Removal of bone(usually in large cysts ,an opening already exist) This stage a window is made by removing a portion of cystic lining like partsch I technique Second unroofing is performed by removing antral lining presents between the cavities Marsupialization by opening into nose or antrum

89. This allows the cyst cavity to become lined with normal ciliated and mucous secreting epithelium regenrating from the respiratory mucosa other than a squamous epithelium Additionally intranasal antrostomy may be performed . Cavity packed with a ribbon gauze soaked withtincture of benzoin or antibiotic ointment

90. Partsch II procedure ( enucleation and primary closure) Enucleation is the process by which the total removal of a cystic lesion is achieved. By definition, it means a shelling- out of the entire cystic lesion without rupture. Enucleation of cysts should be performed with care, in an attempt to remove the cyst in one piece without fragmentation, which reduces the chances of recurrence by increasing the likelihood of total removal. However, maintenance of the cystic architecture is not always possible, and rupture of the cystic contents may occur during manipulation. 1. Enucleation

91. Indications : Enucleation is the treatment of choice Advantages : pathologic examination of the entire cyst can be undertaken the initial excisional biopsy (i.e., enucleation ) has also appropriately treated the lesion. The patient does not have to care for a marsupial cavity with constant irrigations. Disadvantages Normal tissue may be jeopardized Fracture of the jaw Devitalization of associated teeth

92. TECHNIQUE : Aspiration Biopsy of Radiolucent Lesions Mucoperiosteal Flaps Osseous Window Removal of Specimen

93. Aspiration Biopsy of Radiolucent Lesions : Any radiolucent lesion should be aspirated before surgical exploration. This provides the surgeon with valuable diagnostic information regarding the nature of the lesion Mucoperiosteal Flaps : Several varieties of mucoperiosteal flaps are available; the choice depends chiefly on the size and location of the lesion. Access may necessitate extension of the mucoperiosteal flap. The location of the lesion dictates where the flap incisions are to be made. the flap design should provide 4 to 5 mm of sound bone around the anticipated surgical margins mucoperiosteal flaps for biopsies in or on the jaws should be full thickness and incised through mucosa, submucosa , and periosteum

94. Osseous Window : once the flap has been elevated, a rotating bur should be used to remove an osseous window The size of the window depends on the size of the lesion and the proximity of the window to normal anatomic structures such as roots and neurovascular bundles.

95. Technique : A dental curette is used to peel the connective tissues wall of the specimen from surrounding bone. The concave surface of the instrument should always be kept in contact with the osseous surfaces of the bone cavity The bony cavity is inspected after irrigation with sterile saline Any residual fragments of soft tissue within the cavity should be removed with curettes. Once the cavity is devoid of residual pathologic tissue, it is irrigated and the flap is replaced and sutured in its proper location.

96. ENUCLEATION OF CYST

97. Enucleation with Peripheral Ostectomy Removal of 1 to 2 mm of bone beyond the visible margin of the lesion is adequate to improve the cure rate. However, it is difficult to estimate how much bone to remove with a drill. This process is made easier by the use of a vital staining technique. Methylene blue or crystal violet (or any other vital stain) can be painted on the bony walls of the enucleated cyst and allowed to penetrate into the bone. The cavity is then washed out and any bone retaining the stain is removed with a drill . This process usually removes around 2mm of bone in the marrow and about 1 mm of cortical bone .

98. The cavity remaining after a cyst has been enucleated, and stained with methylene blue. (B) The same cavity after removing the methylene blue with a peripheral ostectomy using a pineapple-type bur. Oral Maxillofacial Surg Clin N Am 25 (2013) 21–30

99. Enucleation and treatment of the bony defect with Carnoy solution As a result of the difficulty of enucleating the thin, friable wall of the KCOT as one piece, and due to the small satellite cysts, therefore, treatment should aim to eliminate the possible vital cells left behind in the defect. For this reason a mild, not deeply penetrating, cauterizing agent is used such as Carnoy’s solution consists (Morgan et al., 2005) 3 ml of chloroform 6 ml of absolute ethanol 1 ml of glacial acetic acid 1 g of ferric chloride This should be enough to do cauterization of the remaining cells. In case the cyst has penetrated through the lingual or buccal cortex

100. A KCOT of the left mandible enucleated. The cavity subsequently treated with Carnoy solution. Note the brown appearance of the treated bone, which is often removed with a pineapple bur

101. PROCEDURE Painting sides of cavity with carnoy solution leave it in space for 5 min Wash out the cavity Brown denatured bone removed from the walls of the cavity This technique involves removal of 1 to 2 mm of bone Disadvantages It is nurotoxic when IAN &lingual nerve come in contact with the solution for more than 2 min they become fixed . Nerve should be protected by covering with bone wax .

102. Voorsmit et al. (1981) reported a decreased recurrence rate following treatment with enucleation and Carnoy’s solution (2.5%) compared with enucleation alone (13.5%). According to ( Blanas et al., 2000) enculation of KCOT followed with application of Carnoy’s solution appears to be the least invasive procedure with the lowest recurrence rate. And they reported that adding Carnoy’s solution to the cyst cavity for 3 min after enucleation results in a recurrence rate comparable to that of resection without unnecessarily aggressive surgery.

103. Enucleation and liquid nitrogen cryotherapy The ideal treatment for the KCOT would be enucleation or curettage followed by treatment of the cavity with an agent that would kill the epithelial remnants or satellite cysts. The osseous framework should be left intact to allow for osteoconduction . KCOT <1.5 cm lesions are treated with this technique Liquid nitrogen has the ability to devitalize bone in situ while leaving the inorganic framework untouched. As a result of this, cryotherapy has been used for a number of locally aggressive jaw lesions including :- KCOT Ameloblastoma Ossifying fibroma Cell death with cryosurgery occurs by direct damage from intracellular and extracellular ice crystal formation plus osmotic and electrolyte disturbances.

104. Schmidt and Pogrel (2001) the standardized technique is as follows Enucleation of the cyst. The surrounding tissues are then protected with sterile wooden tongue blades and gauze The cavity is sprayed with liquid nitrogen twice for 1 min (5-min interval) Bone graft can inserted Mucosa is closed with tight sutures Walid Ahmed Abdullah ;Surgical treatment of keratocystic odontogenic tumour:28 January 2011

105. technique of filling the cavity with KY jelly and placing a liquid nitrogen probe in it and freezing the whole cavity. (B) The cryoprobe has been removed, showing the frozen KY jelly and surrounding bony walls of the cyst cavity.

106. The advantages The bone matrix is left in place to act as a clean scaffold for new bone formation A bone graft can be placed immediately to accelerate healing and minimize the risk of a pathologic fracture Decrease of bleeding and scarring.

107. Disadvantages Difficulty in controlling the amount of liquid nitrogen applied to the cavity. The resultant necrosis and swelling can be unpredictable ( Pogrel , 1993; Salmassy and Pogrel , 1995) When the liquid nitrogen cryotherapy is given around the inferior alveolar nerve, it is affected and patients will suffer paraesthesia or anaesthesia. Using this cryotherapy technique seems to be associated with a recurrence rate of around 10%

108. Block resection, with or without preservation of the continuity of the jaw Segmental resection (surgical removal of a segment of the mandible or maxilla without maintaining the continuity of the bone) Marginal resection (surgical removal of a lesion intact, with a rim of uninvolved bone maintaining the continuity of the bone). That results in considerable morbidity, particularly because reconstructive measures are necessary to restore jaw function and aesthetics. Blanas et al. (2000) reported that resection was found to have the lowest recurrence rate (0%) but the highest morbidity rate, while enculation with application of Carnoy’s solution can result in a recurrence rate comparable to that of resection without unnecessarily aggressive surgery.

109. GINGIVAL CYST OF INFANTS (DENTAL LAMINA CYST) Gingival cysts are small, almost multiple white nodules found on the alveolar ridges of newborn and infants up to about 3 months of age. Derived from remnants of dental lamina and resolves without treatment FROMM classified oral embryological inclusion cysts as – - Epistein pearls - Bohns nodules -Dental lamina cysts.

110. Epistein pearls keratin filled nodules found along the midpalatine raphe Derived from entrapped epithelial remants along the line of fusion. Bohns nodules Cysts arising from remanants of mucous glands in the palate away from the midline. Most numerous at the junction of hard and soft palate.

111. Dental lamina cyst Cyst arising from remnants of dental lamina on the crest of alveolar ridge. Clinical features– Appears as small discrete white swellings of alveolar ridge, multiple occassionaly solitary in number.

112. Histological features Cysts with a thin epithelial lining which lacks rete processes. Lumen is filled with degenerated keratin. Treatment No treatment is required. Cysts are superficial and with in weeks they will ruptures and spill their content in to the oral or pharyngeal environment.

113. GINGIVAL CYST OF ADULT Uncommon cyst which may be developmental or acquired in origin. It occurs on free or attached gingiva . Pathogenesis May arise from odontogenic epithelial cell rests. Or by traumatic implantation of surface epithelium. or by cystic degeneration of deep projections of surface epithelium (Ritchey and Orban , 1953).

114. Very rarely, they may be derived from glandular elements ( Traeger , 1961). Most favoured theory of origin is from odontogenic epithelial cell rests derived from the dental lamina, although Shafer et al. (1983) felt that cysts arising from traumatic implantation of surface epithelium may occur. Wysocki et al. (1980), Theory postulates that the lateral periodontal cyst develops from reduced enamel epithelium before eruption of the tooth and the gingival cyst of adults from junctional epithelium (reduced enamel epithelium) after eruption of the tooth.

115. Clinical features: Gingival cyst may occur at any age but more common in adults in 5th and 6th decades of life. Sex- Occurs more in males. Site- More common in mandible in premolar and canine region. It presents as painless swelling less than 1cm in size on the labial aspect of attached or free gingiva . Appearance- Surface may be smooth and color may appear as that of normal gingival or bluish or red when it is blood filled as a result of trauma. Lesions are soft, fluctuant and adjacent teeth are vital.

116. There may be no radiographic change or only a faint round shadow indicative of superficial bone erosion. Radiograph of a gingival cyst in an adult. There is a faint radiographic shadow (marked with arrows) indicative of superficial bone erosion.

117. Histological features Gingival cysts in the adult have a variable histological pattern. Extremely thin epithelium, closely resembling reduced enamel epithelium, with 1–3 layers of flat to cuboidal cells containing arkly staining nuclei. In others, the epithelial lining may be of a rather thicker, stratified, squamous nature without rete ridges. Many of the epithelial cells have pyknotic nuclei and show perinuclear cytoplasmic vacuolation .

118. The epithelial lining of a gingival cyst of the adult (G) lying contiguous to the junctional epithelium (J) of an adjacent tooth.

119. CALCIFYING ODONTOGENIC CYST (CALCIFYING KERATINIZING ODONTOGENIC CYST, GORLIN CYST,CALCIFYING GHOST CELL ODONTOGENIC TUMOR) Rare variety which was initially characterized by Gorlin and associates. WHO 1992 renamed as calcifying cystic odontogenic tumor . Calcifying odontogenic cyst can be classified mainly in to two types Cystic lesion Solid neoplastic lesion

120. classification of the odontogenic ghost cell lesions Group 1 : ‘Simple’ cysts Calcifying odontogenic cyst (COC) Group 2 : Cysts associated with odontogenic hamartomas or benign neoplasms : calcifying cystic odontogenic tumours (CCOT). Group 3 : Solid benign odontogenic neoplasms with similar cell morphology to that in the COC, and with dentinoid Formation Group 4 : Malignant odontogenic neoplasms with features similar to those of the dentinogenic ghost cell tumour Ghost cell odontogenic carcinoma

121. Clinical features Wide age distribution that peaks at 10-19 years of age with mean age of 36 years. second peak incidence occurs during the seventh decade. Aspiration yields a viscous granular yellow fluid. Appears as slowly growing painless swelling of jaw, occasionally the patient may complain of pain. In some cases expanding swelling may destroy the cortical plates Discharge may be present.

122. Radiographic features Location: At least 75% of calcifying odontogenic cyst occur in bone with a nearly equal distribution between the jaws. 75% occur anterior to the first molar especially associated with cuspids and incisors. Periphery and shape well defined and corticated with a curved cyst like shape to ill defined and irregular. Internal structure completely radiolucent or it may show evidence of small foci of calcified material that appears as white fleckes or small smooth pebbles, or it may show larger solid amorphous masses.

123. Radiograph of a calcifying odontogenic cyst of the maxilla. There is a well-demarcated margin and calcifications suggestive of tooth material.

124. Axial CT image shows unilocular radiolucencies with a well-defined border in the right mandible canine to molar area and buccolingual bony expansion. Radio-opaque materials are located at the periphery. Coronal CT image shows unilocular radiolucencies with a well-defined border in the right mandible canine to molar area and buccolingual bony expansion. Radio-opaque materials are located at the periphery. CT FINDINGS The British Journal of Radiology, 85 (2012), 548–554

125. Effects on surrounding structures 20-50% case of cyst is associated with tooth ( commonly cuspid ) and impedes its eruption. Displacement and resorption of roots may occur. Perforation of cortical plates may occur with enlarging lesions.

126. Lining is usually thin about 6 – 8 cell thick, may be thickened in other areas. Lining shows characteristic odontogenic features with reversely polarized basal cell layer. TYPICALLY – GHOST CELLS may be seen in thicker areas of lining. Ghost cells are enlarged, ballooned, ovoid, eosinophilic cells with well defined cell boundaries. Some times many cells may fuse. They represent abnormal keratinization and frequently calcify. Tubular dentinoid and even complex odontome may be found in connective tissue wall close to epithelial lining. Histological features

127. Histological features of a calcifying odontogenic cyst with clusters of fusiform ghost cells and focal calcifications, lying in a stratified squamous epithelium. Histological features

128. Immuno histochemistry Kusuma et al (2005) enamelysin was detected in a portion of the ghost cells in cocs tested Yoshida et al confirmed the presence of amelogenin protein in the cytoplasm of the ghost cells and also few in the epithelial lining Cytokeratin 19 protein was expressed in the epithelail lining cells ,while ghost cells are devoid of staining Bcl-2 protein was expressed in the lining of epithelial cells but ghost cells in only few The epithelial lining cells showed only sporadic ki-67 positive reactions in nuclei

129. Fregnani et al (2003) have shown that CK 8,4,19,AE1/AE3 and 34 β E12 expressed in the suprabasal cells. CK14 and AE1/AE3 cytokeratins expressed in the basal cells of the epithelial lining. Ghost cell expressed only AE1/AE3 and 34 β E12 . Bcl-2 expressed in the basal and supra basal cells but negative in ghost cells . Proliferating cell nuclear antigen (PCNA) and KI-67 expression was higher in the proliferative than in the non proliferative lining epithelium.

130. Treatment Conservative surgical approach. Depending up on the site and size of the lesion and the presence if any other odontogenic elements ( odontome , ameloblastoma like epithelium,ameloblastic fibroma ) simple enuleation or more extensive excision may be required.

131. DIFFERENTIAL DIAGNOSIS Dentigerous cyst Adenomatoid odontogenictumor Ameloblastic fibroodontoma Calcifying epithelial odontogenic tumor

132. GLANDULAR ODONTOGENIC CYST (SIALO-ODONTOGENIC CYST, MUCOEPIDERMOID ODONTOGENIC CYST) Sialo odontogenic cyst was reported by Gardner. Mucoepidermoid odontogenic cyst” because of presence of secretary elements and stratified squamous epithelium. Intrabony and multilocular radiographically with a cystic spaces lined by nonkeratinized stratified squamous epithelium similar to reduced enamel epithelium.

133.   Clinical features Frequency: The glandular odontogenic cyst is a rare lesion. It accounts about 0.2 % of cyst. Age: wide range of age between 10-90 years with peak in sixth decades. Sex- more common in females. Site- More common in mandible than maxilla and more commonly occurs in anterior mandible. Patient may present with painless swelling of jaws or face. Growth is slowly progressive and locally aggressive.

134. Radiographic features Well defined multilocular or unilocular radiolucency Root resorption and displacement of adjacent teeth may be seen. Expansion and thinning of cortical plates with perforation may be seen. unilocular , well defined, radiolucent lesion in the left mandibular horizontal and ascending ramus . The third molar is impacted and displaced towards the lower border

135. CT coronal section of the skull showing well-defined unilocular lesion in the right maxillary sinus confined within the boundaries of maxillary sinus.

136. Histological features Epithelial lining is non keratinized stratified squamous epithelium of variable thickness with a chronic inflammatory infiltration of the connective tissue wall. Microcysts open on the surface of epithelium giving a papillary or corrugated appearance. Numerous goblet cells may be present, mainly in the superficial part of the epithelium. Occasionally, the epithelium is thinner, similar to reduced enamel epithelium. Epithelial thickenings or plaques may be present either in this thin epithelium or in the stratified squamous epithelium. Interface between the epithelium and connective tissue is flat.

137. Parakeratinized squamous epithelial lining exhibiting cuboidal and columnar cells with numerous goblet cells and foci of epithelial cells showing eosinophilic material resembling mucin

138. Treatment Enucleation If the lesion are completely enucleated, further surgery is not indicated because recurrence is unlikely. Patients should be followed for at least 3 years and preferably as long as 7 years. Marsupialisation is recommended if the lesion approach vital structures. For large mulitilocular lesions major treatment modalities are indicated. Include : Peripheral ostecotomy , Marginal resection or partial jaw resection.

139. INFLAMMATORY CYSTS Comprise a group of lesions that arise as a result of epithelial proliferation due to inflammatory causes Types of inflammatory cysts :- Residual cyst Radicular cyst Inflammatory collateral cyst, Pardental cyst, Mandibular infected cyst

140. RADICULAR CYST (PERIAPICAL CYST, APICAL PERIODONTAL CYST) Most common of all odontogenic . Accounts 70% of cysts. Classified as an inflammatory cyst because it is thought that inflammatory products initiate the growth of epithelial components Epithelial lining of radicular cysts may synthesise cytokines that are known to be important in bone resorption .

141. Clinical features Radicular cyst is the most common type of cyst in the jaws. Age-Incidence is greater in third and sixth decades Sex-More common in males than females Site-About 60% occurs in maxilla, 40% occurs in mandible. More common in maxillary anterior region

142. Arise from non vital tooth ( tooth that have lost vitality due to deep caries or deep restoration or previous history of trauma). Most cysts are symptomless and are discovered when periapical radiographs are taken for non vital tooth. Patients may complain of swelling of jaws, slowly enlarging swellings. If it becomes secondarily infected pain may present.

143. On palpation swelling may feel bony hard if cortex is intact. May demonstrate a crackling sound as the cortical plates becomes thinned. Swelling is rubbery and fluctuant if the outer cortex is lost.

144. Radiographic features Location: Epicenter is located approximately at the apex of non vital tooth, Occasionally it appears on the mesial or distal surface of tooth root, at a opening of accessory canal or infrequently in deep periodontal pockets. About 60% found in maxilla around incisors and canines. They also form in relation to non vital deciduous molars.

145. Periphery and shape well defined with a cortical border If secondary infection is present, the inflammatory reaction of surrounding bone may results in loss of cortex or alteration of the cortex in to a more sclerotic border Outline of radicular cyst is usually curved or circular. Internal structure In most cases the internal structure of cyst is radiolucent. Occasionally, dystrophic calcifications may develop in long standing cysts

146. Effects on surrounding structures Large cysts cause displacement and resorption of roots of adjacent teeth. Resorption pattern may be curved outline. cyst may invaginate the maxillary antrum Outer cortical plates may be expanded in a smooth curved or circular shape. Displacement of mandibular canal in an inferior direction may be present.

147. HISTOLOGICAL FEATURES Quiescent epithelium lining a mature, long-standing radicular cyst (H & E). Mucous cells in the surface layer of the stratified squamous epithelial lining of a radicular cyst (H & E).

148. Lined partly / completely by non keratinized epithelium of varying thickness. Epithelium usually shows arcading around the connective tissue. The connective tissue wall shows inflammatory infiltrate mainly in the form of lymphocytes and plasma cells . Hyaline / Rushton bodies are found in epithelium and rarely in connective tissue wall. These are curved or linear structure with eosinophilic staining properties Different types of dystrophic calcification are also seen in connective tissue wall. Mucus cell metaplasia as well as respiratory cells may be seen in the epithelial lining. HISTOLOGICAL FEATURES

149. Treatment Root canal filling ( removal of necrotic pulp; the inflammatory stimuli ). Extraction of the involved non-vital tooth & curettage of apical zone. Root canal filling in association with apicoectomy (direct curretage of the lesion ). Surgery ( epicoectomy & curretage ) is performed for lesions that are persistent,Indicating presence of a cyst or inadequate root canal treatment . Enucleation&Marsupialization .

150. DIFFERENTIAL DIAGNOSIS Periapical granuloma Periapical scar Periapical cemental dysplasia Surgical defect Mandibular infected buccal cyst Traumatic bone cyst

151. Residual cyst Cyst that remains after incomplete removal of original cyst. Shear have stated that the term residual cyst is frequently applied to an apical periodontal cyst which remains after or develops subsequent to extraction of an infected tooth. Shafer and associates also stated that the term can be applied to any cyst of the jaw that remains following surgery

152. Clinical features Asymptomatic and often discovered on radiographic examination of edentulous area. Some expansion of jaw may be present. Pain is present in case of secondary infections. Cysts are usually less than 1cm in size. Age- Highest incidence over 20 years of age with an average age of being 52years Site- Alveolar process and body of jaw bone in edentulous areas. Maxilla is more commonly involved than mandible. Sex- Male predominance in the ratio 3;2.

153. Radiographic features Location: They occur in both jaws . Epicenter is positioned in a periapical location. In mandible the epicenter is above the inferior alveolar canal. Periphery and shape Residual cyst has a cortical margin unless it becomes secondarily infected. It is oval or circular in shape.

154. Internal structure Internal aspect is radiolucent. Dystrophic calcifications may be present in long standing cases. Effects on surrounding structure Causes displacement and resorption of adjacent teeth. Cortical plates may be expanded. In some cases cyst may invaginate the maxillary antrum or depress the mandibular canal.

155. Differential diagnosis : Odontogenic keratocyst Stafnes developmental cyst Compared to OKC residual cyst has greater potential for expansion. The epicenter of stafnes cyst is located below the mandibular canal. Treatment Surgical removal or marsupialization or both if the cyst is large.

156. PARADENTAL CYST ( Buccal bifurcation cyst ( bbc ) Mandibular infected cyst. Inflammatory collateral dental cyst) Both paradental and collateral cyst have same characters. Paradental cyst is of inflammatory origin and that it arises from odontogenic epithelium. Craig suggestes that either the cell rests of malassez or the reduced enamel epithelium may provide the cells of origin.

157. Clinical Features Frequency – It represents 3.7% of odontogenic cysts. Age – BBC most common in second decade. Sex – more common in males than females.

158. Site and clinical presentation Over 60% of all para dental cyst involve the mandibular third molar &there is usually a history of recurrent or persistent pericoronitis . Lesions are most often located in a buccal or distobuccal location and cover the root surface usually involving the bifurcation. The tooth is allways vital. There may be lack or delay in eruption of a mandibular first or second molar.

159. On clinical examination the molar may be missing or the lingual cusp tip may be abnormally protruding through the mucosa, higher than the position of buccal cusps. The first molar is involved more frequently than second molar. A hard swelling may be present buccal to involved molar

160. Radiographic Features If paradental cyst associated with third molars there is usually a distal as well as buccal radiolucency . In all types of para dental cyst the periodontal ligament space is not widened. Location – Mandibular first molar is the most common location of BBC followed by the second molar. Cyst occasionally is bilateral. It is always located in the buccal furacation of affected molar.

161.   Periphery and Shape: In some cases the periphery is not readily apparent, and the lesion may be superimposed over the image of the roots of the molar. In other cases the lesion has a circular shape with a well defined cortical border. Internal structure : Radiolucent.

162. Effects on surrounding structure Most striking character is the tipping of the involved molar so that the root . Tips are pushed into the lingual cortical plate of mandible. Occlusal surface is tipped towards the buccal aspect of mandible. Large cyst may displace or resorb the adjacent teeth. Periosteal bone formation is seen on the buccal cortex adjacent to the Involved teeh . .

163. Treatment BBC is usually removed by conservative curettage. Involved molar should not be removed. BBC do not recur

164. Aneurysmal Bone Cyst Uncommon cyst, found mostly in long bones and spine. CLINICAL FEATURES : - Age : First 3 decades. Sex : Mainly females. Site : molar regions of mandible & maxilla. Signs & symptoms : Hard, rapidly growing swelling which can cause malocclusion. If lesion perforates cortical plates, can cause “egg shell crackling”.

165. Controversy whether lesion arises de novo or from a vascular disturbance in the form of sudden venous occlusion or development of an AV shunt occurring secondarily in a pre existing lesion like central giant cell granuloma , Osteosarcoma etc. Due to the malformation, change in hemodynamic forces occurs which can lead to ABC. PATHOGENESIS

166. Classically seen as a unilocular , ovoid / fusiform lucency which balloons the cortical plates. Teeth displacement and root resorption also observed. Lesions are usually unilocular but longer-standing lesions may show a ‘soap-bubble’ appearance and may become progressively calcified RADIOLOGICAL FEATURES

167. Radiograph of an aneurysmal bone cyst involving the angle and ascending ramus of the mandible. There is a ballooning expansion of the cortex.

168. It consist of many capillaries and blood-filled spaces of varying size lined by flat spindle cells and separated by delicate loose-textured fibrous tissue Most lesions contain small multinucleate cells and scattered trabeculae of osteoid and woven bone . In some of the solid areas, sheets of vascular tissue, containing large numbers of multinucleate giant cells, fibroblasts, haemorrhage and haemosiderin , look very much like giant cell granuloma of the jaws The diagnosis is made primarily on the basis of the clinical and radiological features because histologically such solid lesions may be indistinguishable from giant cell granuloma . Histological features

169. Histological features Aneurysmal bone cyst in which the solid areas have histological features identical to those of the central giant cell granuloma of the jaws (H & E). Aneurysmal bone cyst of the mandible. The solid areas show the features of cemento-ossifying fibroma and a portion of one of the many cystic spaces is present at the top of the photomicrograph (H & E).

170. Conventional ameloblastoma CEOT Central giant cell granuloma DIFFERENTIAL DIAGNOSIS

171. Also called as Hemorrhagic bone cyst, or Traumatic bone cyst. Commonly seen in mandible, rare in maxilla. Identical to solitary bone cyst of humerus in children and adolescents. Solitary Bone Cyst

172. Age : Young individuals Sex : Equal Site : Body and symphysismenti of mandible. CLINICAL FEATURES

173. None of the theories are certain about exact cause. First theory – cyst may follow trauma to bone which causes intra medullary hemorrhage which fails to organize. This clot subsequently liquefies - CYST. Recent theory osteogenic cells fail to differentiate locally and thus instead of bone, the undifferentiated cells form synovial tissue. PATHOGENESIS

174. Asymptomatic. Rarely, swelling and pain may be seen. Half of all patients give a history of trauma to the area. Signs & symptoms

175. Appears as a lucency with irregular but well defined edges and slight cortication. On occlusal view the radiolucency is seen to extend along cancellous bone. RADIOLOGICAL FEATURES Radiograph of a solitary bone cyst involving an extensive area in the right body of the mandible. This example has a well-defined margin with cortication. Interradicular scalloping is a prominent feature.

176. Lumen not lined by any epithelium (Pseudo cyst). Wall shows loose fibro vascular connective tissue. Hemorrhage and hemosiderin pigment usually present. Multinucleated giant cells scattered within the connective tissue. Adjacent bone shows osteoclastic resorption on inner surface. HISTOLOGICAL FEATURES A solitary bone cyst of the jaw. The lining is composed of loose vascular fibrous tissue with osteoclastic activity on the surface of the adjacent bone (H & E).

177. Mucocele It is a common lesion of the oral mucosa that results from an alteration of minor salivary glands due to a mucous accumulation. Mucocele involves mucin accumulation causing limited swelling Two types of mucocele can appear - extravasation and retention. Extravasation mucocele results from a broken salivary glands duct and the consequent spillage into the soft tissues around this gland. Retention mucocele appears due to a decrease or absence of glandular secretion produced by blockage of the salivary gland ducts When located on the floor of the mouth these lesions are called ranulas because the inflammation resembles the cheeks of a frog .

178. Pathogenesis Yamasoba et al. highlight two crucial etiological factors in mucoceles : traumatism and obstruction of salivary gland ducts. Mucoceles can appear by an extravasation or a retention mechanism. Extravasation mucoceles are caused by a leaking of fluid from surrounding tissue ducts or acini . This type of mucocele is commonly found on the minor salivary glands. Physical trauma can cause a leakage of salivary secretion into surrounding submucosal tissue. Inflammation becomes obvious due to stagnant mucous resulting from extravasation

179. Clinical features Frequency: Mucocele of the mouth are very common Age : peak frequency in third decade Sex: Equal gender frequency Retention cysts are some are found some what more frequently in women than in men Site: The great majority are found in the lower lip,Very few occurred in the upper lip Retention cysts occur in the floor of the mouth followed by Buccal mucosa , Lower lip Palate tongue Upper lip Extravasation mucocele have been reported in the anterior ventral aspect of the tongue associated with glands of baldin and nuhn

180. There is no clinical difference between extravasation and retention mucoceles . Mucoceles present a bluish, soft and transparent cystic swelling which frequently resolves spontaneously. The blue colour is caused by vascular congestion and tissular cyanosis of the tissue above and the accumulation of fluid below . Mucoceles of the minor salivary glands are rarely larger than 1.5 cm in diameter and are always superficial. Mucoceles found in deeper areas are usually larger. Mucoceles can cause a convex swelling depending on the size and location, as well as difficulties in speaking or chewing .

181. HISTOLIOCAL FEATURES Retention mucoceles Generally well defined with an epithelial wall covered with a row of cuboidal or flat cells produced from the excretory duct of the salivary glands . Compared to extravasation mucoceles , retention mucoceles show no inflammatory reaction and are true cysts with an epithelial covering Extravasation mucoceles These are pseudocysts without defined walls. The extravasated mucous is surrounded by a layer of inflammatory cells and then by a reactive granulation tissue made up of fibroblasts caused by an immune reaction. Even though there is no epithelial covering around the mucosa, this is well encapsulated by the granulation tissue

182. TREATMENT Small mucoceles may require no surgical treatment Small mucoceles can be removed completely with the marginal glandular tissue . In the case of larger mucoceles , marsupialization would avoid damage to vital structures

183. Parasitic cysts Hydated cyst It occurs in hydatid disease or echinococcosis Caused by the larvae of E.granulosus . The majority of hydatid cysts are seen in the liver and lungs . Hydatidosis commonly appear as cystic lesions and these characteristically grow slowly (1—2 cm per year) . The location, the size, and the pressure caused by the enlarging cyst, define the symptoms CT and MRI are the main facilities of diagnostic imaging.

184. Corona MRI revealed a cystic mass located on the right submandibular region.

185. Intermediate non nucleated layer with Germinative layer forming brood capsules on its inner aspect The scolies are formed in these brood capsules HISTOLOGICAL FEATURES

186. Treatment Since there is no effective medical treatment . Surgical removal without causing any spillage of the hydatid cyst’s contents is still the most effective medical treatment . If it is not performed, the lesions are very likely to transform into an untreatable multiple hydatosis or anaphylactoid reaction may occur

187. Cysticercus cellulose (pork tape warm) The adult worm may be ingested in inadequately heated or frozen pork. This lives attached to the small intestine . They penetrate the intestinal mucosa and are then distributed through the blood vessels and lymphatics . Where they develop into cysticerci .

188. Clinical features Age - range 3 to 70 years Sex - Male : female (1:1) Site- Most common site is tongue followed by buccal mucosa and lips Asymptomatic swellings covered by normal appearing mucosa When cut they contain clear watery fluid and a colied white structure apparantly attached to the inner aspect of the cyst

189. Histological features Dense fibrous outer capsule derived from host tissue Dense inflammatory infiltration seen Foci of dystrophic calcifications are present in the capsule A delicate double layered membrane consisting of an outer hyaline layer and inner cellular layer This membrane contains larval form of T. solium cysticercus cellulose removed from tongue containing t.solium larva form in double layerd membrane

190. Treatment Drug therapy is the treatment of choice. High doses of  praziquantel ( 50 mg/kg per day for 15-30 days) Albendazole (10-15 mg/kg per day  for 8 days) cysticercosis   also is treated by surgical excision of the cysts .

191. References Mervyn Shear and Paul M.Speight Cysts of Oral and Maxillofacial Regions –fourth edition Laskin - 2nd volume Ceylan Z. Cankurtaran , MD et al Ameloblastoma and Dentigerous Cyst Associated with Impacted Mandibular Third Molar Tooth ;2010 Natl J Maxillofac Surg. 2014 Jul-Dec; 5(2): 172–179 (Shear and Pindborg ,1975: Wysocki et al 1980,Cohen et al 1984: Altini and Shear ,1992) Dentomaxillofacial Radiology (2011) 40, 133–140 ’ 2011 The British Institute of Radiology Walid Ahmed Abdullah Surgical treatment of keratocystic odontogenic tumour: A review article 2011 Oral Maxillofacial Surg Clin N Am 25 (2013) 21–30 The British Journal of Radiology, 85 (2012), 548–554 Oral Maxillofacial Surg Clin N Am 25 (2013) 21–30

192. THANK YOU