cysts of the oral and maxillofacial region

easily understandable

1. Cysts Of The Oral And Maxillofacial Region

2. DEFINATION A Cyst is a pathological cavity having fluid , semifluid or gaseous contents and which is not created by the accumulation of pus. Most cysts, but not all, are lined by epithelium . (KRAMER 1974). May occur within the bone or soft tissue Asymptomatic or associated with swelling and pain

3. Cysts are generally slow growing , expansile lesions They grow by hydraulic expansion Radiographically , they often appear radiolucency surrounded by thin radioopaque border 10

4. TYPES OF CYSTS TRUE CYSTS: that which is lined by epithelium e.g dentigerous cyst, radicular cyst etc. PSEUDO CYSTS: not lined by epithelium, e.g. Solitary bone cyst, Aneurismal bone cyst etc

5. PARTS OF A CYST Cyst has following parts: WALL (made of connective tissue ) EPITHELIAL LINING LUMEN OF CYST

6. CLASSIFICATION

7. I. Cysts of the jaws 1 Developmental Origin a) Odontogenic Gingival cyst of infants Odontogenic keratocyst Dentigerous cyst Eruption cyst Gingival cyst of adults Developmental lateral periodontal cyst Botryoid odontogenic cyst Glandular odontogenic cyst Calcifying odontogenic cyst b ) Non-odontogenic Midpalatal raphé cyst of infants Nasopalatine duct cyst Nasolabial cyst 2 Inflammatory Origin Radicular cyst, apical and lateral Residual cyst Paradental cyst and juvenile paradental cyst Inflammatory collateral cyst B. NON-EPITHELIAL-LINED CYSTS Solitary bone cyst Aneurysmal bone cyst A. EPITHELIAL-LINED CYSTS

8. II. Cysts associated with the maxillary antrum Mucocele Retention cyst Pseudocyst Postoperative maxillary cyst

9. III. Cysts of the soft tissues of the mouth , face and neck Dermoid and epidermoid cysts Lymphoepithelial (branchial) cyst Thyroglossal duct cyst Anterior median lingual cyst (intralingual cyst of foregut origin) Oral cysts with gastric or intestinal epithelium ( oral alimentary tract cyst) Cystic hygroma Nasopharyngeal cyst Thymic cyst Cysts of the salivary glands: mucous extravasation cyst ; mucous retention cyst; ranula ; polycystic ( dysgenetic) disease of the parotid Parasitic cysts: hydatid cyst; Cysticercus cellulosae; trichinosis

10. PATHOGENESIS THREE STAGES Cyst initiation Formation Cyst enlargement or expansion Initiation Formation Enlargement

11. CYST INITIATION Initiation results in the proliferation of the epithelial cells and the formation of small cavity . a. Cell Rests of Malassez : Remanants of Hertwigs epithelial root sheath b . Reduced Enamel Epithelium : Residual epithelial cells surrounds the crown of the tooth c. Cell Rests of Serres (Dental Lamina) : Islands of epithelial cells that originate from the oral epithelium

12. CYST ENLARGEMENT Harris (1974) Postulated the theories Mural growth a) Peripheral cell division b ) Accumulated contents Hydrostatic a ) Secretion b ) Transuduation & exudation c ) Dialysis

13. Mechanism regarding enlargement Increase in the volume of its contents. Increase in the surface area of the sac or epithelial proliferation. Resorption of surrounding bones.

14. Frequency of Epithelial Cysts of Jaws

15. DENTIGEROUS CYST

16. Definition: 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 (REE) and the tooth crown.

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

18. CLINICAL FEATURES AGE : 1st to 3rd decades . GENDER : more frequently in males than in females. SITE : 2/3 rd of follicular cyst associated with unerupted mandibular teeth , primarily III molar. Maxillary canine Mandibular premolar Maxillary 3 rd Molar Supernumerary tooth also can be involved

19. Signs & symptoms Most cysts grow to a large size before being discovered accidentally while observing a dental x ray to detect the cause of an unerupted tooth . Large lesions can cause cortical expansion , leading to facial asymmetry , teeth displacement , root resorption , even pain, if infected.

20. RADIOLOGICAL FEATURES Manifests as unilocular , well defined , ‘lucency with sclerotic margins, associated with crown of impacted / unerupted tooth. A large DC may show persistence of bony trabeculae, giving the appearance of multilocularity.

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

22. Radiographic features A central type of dentigerous cyst . Note resorption of the root of the first mandibular molar

23. Radiographic features Radiograph of two dentigerous cysts in the same patient. The cyst on the right is a lateral type ; that on the left is a circumferential type

24. HISTOLOGICAL FEATURES A . NON INFLAMMED TYPE : Lining derived from reduced dental epithelium , consists of 2-4 cell layers of non keratinized epithelium, without rete ridges. Wall composed of thin fibrous connective tissue appearing immature , as it is derived from the dental papilla.

25. NON INFLAMMED TYPE NON INFLAMED dentigerous cyst shows a thin. nonkeratinized epithelial lining.

26. HISTOLOGICAL FEATURES B. INFLAMED TYPE : Lining shows varying degrees of hyperplasia with rete ridges and occasionally even keratinization . Wall is composed of mature connective tissue which shows infiltration by chronic inflammatory cells . Focal areas of mucous cells can be seen in the lining. Small odontogenic epithelial islands can be seen in the wall.

27. INFLAMED TYPE INFLAMED DENTIGEROUS CYST shows a thicker epithelial lining with hyperplastic rete ridges. The fibrous cyst capsule shows a diffuse chronic inflammatory infiltrate

28. DIFFERENTIAL DIAGNOSIS Although it presents a unique feature, yet some lesions must be considered in its differential diagnosis : Unicystic ameloblastoma Adenomatoid odontogenic tumor.

29. COMPLICATIONS Recurrence due to incomplete surgical removal. Development of ameloblastoma either from lining epithelium or from odontogenic islands in the connective tissue wall. Development of squamous cell carcinoma from same two sources. Development of mucoepidermoid carcinoma from mucus secreting cells in the lining.

30. ODONTOGENIC KERATOCYST

31. The odontogenic keratocyst is a distinctive form of developmental odontogenic cyst that deserves special consideration because of its specific histopathologic features and clinical behavior . There is general agreement that the odontogenic keratocyst arises from cell rests of the dental lamina . This cyst shows a different growth mechanism and biologic behavior from the more common dentigerous cyst and radicular cyst.

32. Growth may be related to unknown factors inherent in the epithelium itself or enzymatic activity in the fibrous wall . Several investigators suggest that odontogenic keratocysts be regarded as benign cystic neoplasms rather than cysts 39

33. CLINICAL FEATURES AGE : Wide age range 1 st to 9 th decade Peak frequency in the 2 nd and 3 rd decades. GENDER : more frequently in males than in females. SITE : The mandible > maxilla 50 % cases occur in angle region and extend to ascending ramus and forwards to body of mandible .

34. site diSTRIbuTION

35. CLINICAL FEATURES P ain , swelling or discharge. Occasionally, paraesthesia of the lower lip or teeth . Develop pathological fractures . In many instances - free of symptoms until the cysts have reached a large size, involving the maxillary sinus and the entire ascending ramus, including the condylar and coronoid processes. OKC tends to extend in the medullary cavity and clinically observable expansion of the bone occurs late.

36. GORLIN-GOLTZ syndrome , characterized by Multiple nevoid basal cell epitheliomas Odontogenic Keratocyst of the jaws Bifid ribs– sixth rib Plantar & palmar pits Occular hypertelorism Frontal bossing Ectopic calcifications

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38. RADIOGRAPHIC FEATURES OKC demonstrate a well-defined radiolucent area with smooth and often corticated margins . Large lesions, particularly in the posterior body and ascending ramus of the mandible, may appear multilocular An unerupted tooth is involved in the lesion in 25% to 40% of cases; in such instances, the radiographic features suggest the diagnosis of dentigerous cyst

39. 46 Multilocular radiolucency Uni locular radiolucency

40. Multiple okc 47

41. 48 1. REPLACEMENTAL – Cyst forms in place of normal tooth by degeneration of dental lamina. 2. EXTRANEOUS – OKC occurs in ascending ramus, away from tooth bearing areas Radiographic variants of okc

42. 49 3. COLLATERAL – OKC occurs adjacent to root of tooth, mimicking a lateral periodontal cyst. 4. ENVELOPMENTAL – This is an odontogenic keratocyst which embraces or envelopes an adjacent unerupted tooth.

43. HISTOLOGIC FEATURES Uniform layer of stratified squamous epithelium, usually 6-8 cells in thickness . Flat epithelium and connective tissue interface absence of rete ridge. Basal cell layer has columnar / cuboidal cells with reversely polarized nuclei , imparting a “picket fence” or “ tombstone ” appearance . Luminal surface - 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 .

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45. 52 Parakeratinized OKC

46. 53 Orthokeratinized OKC

47. Satellite microcysts Satellite microcysts in the wall of an odontogenic keratocyst that appear to be arising directly from an active dental lamina .

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

49. COMPLICATIONS IN OKC : Malignant transformation of cyst lining rare , but has been reported. Recurrence – high rate of recurrence. REASONS FOR RECURRENCE : Thin , fragile lining is very difficult to remove completely. New cysts develop from satellite cysts left behind. Some cysts may be left behind in cases of Gorlin – Gotz syndrome. New cysts can also develop from basal cells of overlying oral epithelium , especially in ramus – 3rd molar region.

50. ERUPTION CYST

51. ERUPTION CYST Typical c/f of an eruption cyst. Note a bluish colored, dome shaped swelling over the unerupted molar. The dentigerous cyst develops around the crown of an unerupted tooth lying in the bone , The eruption cyst occurs when a tooth is impeded in its eruption within the soft tissues overlying the bone. Eruption cysts involving the maxillary permanent incisors.

52. PATHOGENESIS

53. CLINICAL FEATURES AGE : found in children of different ages, and occasionally in adults if there is delayed eruption SITE : most commonly associated with the first permanent molars and the maxillary incisors

54. Radiological features The cyst may throw a soft-tissue shadow, but there is usually no bone involvement except that the dilated and open crypt may be seen on the radiograph.

55. HISTOLOGICAL FEATURES Show surface oral epithelium on the superior aspect. The underlying lamina propria shows a variable inflammatory cell infiltrate. The deep portion of the specimen, which represents the roof of the cyst, shows a thin layer at nonkeratinizing squamous epithelium A cystic epithelial cavity can be seen below the mucosal surface.

56. GINGIVAL CYST OF ADULTS

57. pathogenesis A number of suggestions have been made about the pathogenesis of the gingival cyst in adults. It was originally proposed that they may arise from odontogenic epithelial cell rests ; or by traumatic implantation of surface epithelium ; or by cystic degeneration of deep projections of surface epithelium

58. origin Cystic transformation of dental lamina, traumatic implantation of surface epithelium Dome shaped soft, fluctuant swelling which is <1cm in diameter Lesion is slow growing and painless Adjacent teeth usually vital

59. Clinical features AGE : 5 th – 6 th decade of life SITE : mandibular canine and Pre Molar area ; attached gingiva or interdental papilla Signs and symptoms : Slowly enlarging, well circumscribed painless swelling. Invariably occurs on facial aspect of free / attached gingiva . Surface of lesion is smooth and of normal color . Fluctuant lesion, adjacent teeth are vital

60. Radiological features Radiograph of a gingival cyst in an adult. There is a faint radiographic shadow (marked with arrows) indicative of superficial bone erosion.

61. Histology H/p features identical to Lateral periodontal cyst . Some cysts lined by thin, flattened stratified squamous epithelium. Sometimes, focal thickenings ( Plaques ) may be found within the lining.

62. LATERAL PERIODONTAL CYST

63. LATERAL PERIODONTAL CYST Uncommon , but well recognized type of odontogenic cyst . The designation ‘lateral periodontal cyst’ is confined to those cysts that occur in the lateral periodontal position and in which an inflammatory etiology and a diagnosis of collateral OKC have been excluded on clinical and histological grounds (Shear and Pindborg, 1975).

64. CLINICAL FEATURES Age : 20 – 60 years, peak in 6th decade . Sex : Male predilection. Site : Lateral PDL regions of mandibular premolars , followed by anterior maxilla

65. Signs & symptoms Usually asymptomatic as it occurs on the lateral aspect of root of tooth . Occasionally pain and swelling may occur . Associated teeth are vital , unless otherwise affected . Cysts are < 1cm in size, except for BOTRYOID VARIETY which is larger and also a multilocular lesion.

66. Radiological features Round to ovoid ‘ lucency with sclerotic margins . Cyst can be present anywhere between cervical margin to root apex . Radiographically, it can be confused with collateral OKC .

67. Radiological features Lateral periodontal cyst. Radiolucent lesion between the roots of a vital mandibular canine and first premolar. Lateral periodontal cyst. A larger lesion causing root divergence.

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

69. HISTOLOGICAL FEATURES Lateral periodontal cyst which in part has a thin, nonkeratinised stratified squamous epithelial lining resembling reduced enamel epithelium. Two epithelial plaques are seen.

70. CALCIFYING ODONTOGENIC CYST

71. CALCIFYING ODONTOGENIC CYST Also called as Odontogenic ghost cell cyst or Gorlin cyst . It Has many features of odontogenic tumor , - placed in the category of tumors in the latest WHO classification of odontogenic cysts and tumors . In the latest WHO publication on odontogenic tumours (Prætorius and Ledesma-Montes, 2005) it was classified as a benign odontogenic tumour and was renamed calcifying cystic odontogenic tumour (CCOT).

72. Clinical FeAtures Age : Wide range, peak in 2 nd decade. Sex : Equal. Site : Anterior segment of both jaws

73. pathogenesis COC is a unicystic process and develops from the reduced dental epithelium or remnants of dental lamina . The cyst lining has the potential to induce formation of dentinoid or even odontom a in adjacent CT wall.

74. 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

75. Signs & symptoms Swelling is the commonest complaint, seldom associated with pain . Intraosseous lesions can cause hard bony expansion and resulting facial asymmetry . Displacement of teeth can also occur.

76. RADIOLOGICAL FEATURES Intraosseous lesions produce well defined lucency which is usually unilocular . Irregular calcified masses of varying sizes may be seen within the lucency . Displacement of root/roots with or without root resorption and expansion of cortical plates also seen

77. Radiograph of a calcifying odontogenic cyst with well-demarcated margins extending from the right to the left premolar regions of the mandible. Numerous calcifications are present, some suggestive of small denticles.

78. Histological features 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 , e osinophilic 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.

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

80. Histological features In this calcifying odontogenic cyst, there are sheets of ghost cells and a focal area in which there has been induction of a strip of dysplastic dentine (dentinoid).

81. DIFFERENTIAL DIAGNOSIS Based on radiographic appearance, following lesions must be included in the provisional diagnosis – Ameloblastoma CEOT AOT Ameloblastic fibro odontoma

82. RADICULAR CYST

83. RADICULAR CYST Also called APICAL PERIODONTAL CYST Radicular cysts are the most common inflammatory cysts and arise from the epithelial residues in the periodontal ligament as a result of periapical periodontitis following death and necrosis of the pulp . Quite often a radicular cyst remains behind in the jaws after removal of the offending tooth and this is referred to as a residual cyst .

84. PATHOGENESIS PHASE OF INITIATION: Accepted generally that rests of Malassez included within a developing periapical granuloma proliferates to form the lining of radicular cyst. Some product of non vital pulp can be responsible which simultaneously evokes an inflammatory response in CT.

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86. PATHOGENESIS 2. PHASE OF CYST FORMATION: Can occur in two possible ways. One theory states that epithelium proliferates and covers the bare connective tissue surface of the abscess cavity. Another theory – cyst cavity forms within proliferating epithelium as the cells in center move away from their nutrient source .

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88. PATHOGENESIS 3. PHASE OF ENLARGEMENT : Enlargement occurs by collection of fluid within the lumen of the cyst. Osmosis plays an important role here as the cyst wall appears to have the properties of a semi permeable membrane.

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90. CLINICAL FEATURES Age : Peak in 3 rd , 4 th and 5 th decades. Sex : Slightly more in males . Site : Maxillary anterior region . Frequency : Commonest cystic lesion of jaws.

91. Signs & symptoms Primarily symptom less . Discovered accidentally during routine dental X ray exam. Slowly enlarging hard bony swelling initially. Diagnostic criteria – associated teeth are non vital Rare in deciduous teeth.

92. RADIOLOGICAL FEATURES Classically presents as round / ovoid lucency with sclerotic borders and associated with pulpally affected tooth / teeth. If infection supervenes, the margins become indistinct, making it impossible to distinguish it from a peripaical granuloma.

93. HISTOLOGICAL FEATURES 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

94. 101 Hyaline bodies in the epithelial lining of a radicular cyst (H & E).

95. HISTOLOGICAL FEATURES Cholesterol crystals in from of clefts are often seen in the connective tissue wall, inciting a foreign body giant cell reaction. 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. Keratinization if found is due to metaplasia and must not be confused with an OKC.

96. 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).

97. HISTOLOGICAL FEATURES Cholesterol clefts and multinuclear foreign body giant cells in a radicular cyst (H& E ).

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99. Residual cysts Radiographic appearance of a large residual cyst left behind after extraction of 1 st mandibular molar. The histopathological features of the residual cyst are similar to conventional radicular cysts . However, because the cause of the cyst has been removed , Residual cysts may progressively become less inflamed so that eventually the cyst wall is composed of uninflamed The epithelial lining may be thin and regular and indistinguishable from a developmental cyst such as a dentigerous cyst or lateral periodontal cyst.

100. DIFFERENTIAL DIAGNOSIS: Following lesions must be distinguished from other periapical radiolucencies– Periapical granuloma Peripaical cemento – osseous dysplasia ( early lesions )

101. Paradental Cysts

102. Paradental Cysts A cyst of inflammatory origin- occurring on lateral aspect of root of partially erupted mandibular 3 rd molar with an associated history of pericoronitis Age : 20-40 years Tooth is vital Facial swelling Facial sinus in some cases

103. Radiographic features Affected tooth is tilted Well demarcated RadioLucency Distal to partially erupted tooth Lamina Dura is intact New bone may be laid down a b

104. Histological features The cysts are lined by a hyperplastic , non keratinised , stratified squamous epithelium which may be spongiotic and of varying thickness . An intense inflammatory cell infiltrate was present associated with the hyperplastic epithelium fibrous capsule is the seat of an intense chronic or mixed inflammatory cell infiltrate .