odontogenic keratocyst

odontogenic keratocyst or keratocystic odontogengic tumor.
it is always in dicussion due to its high recurrunce rate and presence of daughter cyst.

1. CASE PRESENTATION ODONTOGENIC KERTOCYST Presented by- Dr. S ujay P atil Dept of maxillofacial surgery

2. PATIENT DETAILS 35 year old Female reported to BVP OPD with C/C/O swelling in lower right back tooth region since 6 months. Swelling was gradually increased in last 3 months. It was not associated with pain.

3. ON EXAMINATION Swelling with 42 to 46. It was firm. Intra oral bulge on buccal side was present. Missing 45. No loss of sensation.

4. INVESTIGATIONS Complete heamogram Routine urine Blood glucose level- Random Serum electrolyte Serum creatinine HIV/ HBsAg antigen test PT-INR OPG CBCT

5. RADIOGRAPHIC EXAMINATION

6. Histologic examination

7. PROVISIONAL DIAGNOSIS On the basis of the patient’s history and the clinical radiographic and histological findings, a provisional diagnosis of Benign cyst was made.

8. Treatment Plan RCT 43, 44 and 46. Placement of an lower arch bar. Enucleation with open dressing.

9. INTRA OPERATIVE

10. Painting and draping done in usual manner LA infiltrated in lower right vestibule.

11. Vestibular degloving incision Dissection done Corticotomy done Cyst exposed

12. Microscopic examination

13. Diagnosis

14. Odontogenic Kerato -Cyst.

15. Post operative

16. Postoperative observation

17. Postoperative recovery was uneventful. Healing progressed satisfactorily. 2 months after we removed arch bar as bone healing appears satisfactory. In view of these satisfactory findings no further surgical intervention was considered necessary, and it was decided to examine the patient periodically.

18. DISCUSSION

19. INTRODUCTION 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’. Most cysts, but not all, are lined by epithelium. Odontogenic keratocyst is a distinctive form of developmental odontogenic cyst . Odontogenic keratocysts (OKCs) are known for their propensity to recur .

20. Various terminologies cholesteatoma ( Hauer , 1926; Kostecka , 1929) ‘odontogenic keratocyst ’ was introduced by Philipsen (1956). ‘primordial cyst’ (Shear, 1960a; Shear and Altini , 1976; Pindborg et al., 1971) ‘ keratocystoma ’ (2003, Shear) ‘keratinising cystic odontogenic tumour’ (Reichart and Philipsen , 2004) ‘ keratocystic odontogenic tumour’ ( Philipsen , 2005) “ keratocystic odontogenic tumor.”(latest WHO classification of odontogenic tumors )

21. Etiology and Pathogenesis The etiology is probably closely related to the development of the dental lamina and in particular remnants of it after this organ has served its purpose. OKCs that occur in the dentate areas of both the maxilla and mandible probably derive from those remnants. Epithelial islands that are derived from the dental lamina are mainly found in the gingiva and periodontal ligament. It is not known why it develop from such epithelial residues or epithelial island. The result of increased osmotic pressure within the lumen of the cyst. This mechanism does not appear to hold true for odontogenic keratocysts , and their growth may be related to unknown factors inherent in the epithelium itself or enzymatic activity in the fibrous wall.

22. There is plenty of evidence that the majority of epithelial islands, as found in the wall of OKCs, are in fact located in the mucosa that is overlying the OKC and attached to it. This is the reason why it is thought that offshoots of the basal layer of the epithelium of the oral mucosa may also be involved in the etiology of OKCs. Epithelial islands and/or microcysts are found in approximately 50% of the cases in the overlying, attached mucosa. If one removes such an OKC some of these epithelial residues may be left behind which may later give rise to a new keratocyst .

23. odontogenic keratocysts make up 3% to 11% of all odontogenic cysts.

24. Clinical presentation Age between 10 and 40 years. Slight male predilection. The mandible is involved in 60% to 80% of cases, with a marked tendency to involve the posterior body and ascending ramus.

25. Tend to grow in an anteroposterior direction within the medullary cavity of the bone without causing obvious bone expansion. Multiple odontogenic keratocysts may be present - the nevoid basal cell carcinoma ( Gorlin ) syndrome. It demonstrates a well-defined radiolucent area with smooth and often corticated margins . An unerupted tooth is involved in the lesion in 25% to 40% of cases - the cyst has presumably arisen from dental lamina rests near an unerupted tooth and has grown to envelop the unerupted tooth. Resorption of the roots of erupted teeth adjacent to it is less common.

26. Histopathological features Cystic lumen may contain a clear liquid that is similar to a transudate of serum, or it may be filled with a cheesy material, consists of keratinaceous debris. Thin fibrous wall is devoid of any inflammatory infiltrate. Epithelial lining is composed of a uniform layer of stratified squamous epithelium, usually six to eight cells in thickness. Epithelium and connective tissue interface is usually flat , and rete ridge formation is inconspicuous. Detachment of portions of the cyst-lining epithelium from the fibrous wall is commonly observed.

27. 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(7% to 26% of cases in various reported series). Orthokeratinizing cysts - Some investigators recognize as a microscopic variant and include this lesion as a subtype. KCA – Kunnas et al 1986

28. Recurrence Recurrence rate of approximately 30%. More often in mandibular odontogenic keratocysts , particularly those in the posterior body and ascending ramus. Recur within 5 years of the original surgery Many surgeons recommend peripheral ostectomy of the bony cavity with a bone bur to reduce the frequency of recurrence. chemical cauterization of the bony cavity with Carnoy’s solution after cyst removal.

29. Reasones ??? Tendency to multiplicity . Occurrence of satellite cysts which may be retained during an enucleation procedure. Linings are very thin and fragile , particularly when the cysts are large. Innate tendency to develop such cysts , then any remnants of dental lamina may form the target for new OKC formation.{ Soskolne and Shear (1967)} OKCs may also arise from proliferations of the basal cells of the oral mucosa , particularly in the third molar region and ascending ramus of the mandible.{ Stoelinga (1971a, 2001, 2003a) and Stoelinga and Peters (1973)}

30. TREATMENT

31. It is important to keep in mind the possible reasons of recurrence . Treatment should aim at elimination of possible vital cells left behind in the defect - from the original lining or derived from microcysts in the wall. The choice of treatment approach should be based on the size of the cyst, recurrence status, and radiographic evidence of cortical perforation.

32. Enucleation followed by open packing. The resulting cavity was irrigated with mixture of normal saline + chlorhexidine gluconate for a full-of glass. Packed with iodoform gauze impregnated with bacitracin ointment to minimize the risk of recurrence in each recall visits. The benefit of this protocol lies in the minimal surgical morbidity, associated structures such as the inferior alveolar nerve and developing teeth are less vulnerable to the damage.

33. Marsupialisation with open dressing. Continuous irrigation and packing with iodoform gauze dressing. After 10 months enucleation.

34. Brondum and Jensen(1992) and Marker et al(1997). After cystotomy and incisional biopsy, some surgeons have treated it by insertion of a polyethylene drainage tube to allow decompression and subsequent reduction in size of the cystic cavity. It results in thickening of the cyst lining, allowing easier removal with an apparently lower recurrence rate. Disadvantages - it requires two surgical procedures and the treatment time necessary is comparatively long.

35. Instead of the use of Carnoy’s solution, liquid nitrogen Used to freeze the defect. Much more complicated. Indicated in selected patients. Block resection , with or without preservation of the continuity of the jaw. Drastic method - considerable morbidity Reconstructive measures are necessary to restore jaw function and esthetics . Provide adequate results when it includes the overlying attached oral mucosa.

36. Follow Up The literature suggests that most recurrences will present the first 5 years after primary treatment . The recommended follow-up for OKCs is once a year the first 5 years postoperatively . Because recurrences or newly developed OKCs may also present late, a follow-up once every 2 years thereafter seems a reasonable policy.

37. Prognosis Other than the tendency for recurrences, the overall prognosis is good . In extremely rare instances, extend up into the skull base region. A few examples of carcinoma arising in it have been reported, but the propensity for an odontogenic keratocyst to undergo malignant alteration is no greater and is possibly less than that for other types of odontogenic cysts. Should be evaluated for manifestations of the nevoid basal cell carcinoma syndrome particularly if the patient is in the first or second decade of life .