Odontogenic keratocyst- A case presentation

OKC is an aggressive form of developmental cyst. Here is a case observed by Dr. Binaya Subedi.

1. A case presentation on Odontogenic Keratocyst Binaya Subedi BDS Intern School Of Dental Sciences, CMC

2. Demographic Details Hospital No: 76133809 Name: Rewati Pariyar Age/sex : 74Y/ F Address : Kawasoti

3. Chief Complaints Patient complains of swelling in lower front region of jaw since 3 months.

4. History of Presenting illness She was in her usual state of health, when she noticed a hard swelling in lower front region of jaw 3 months back, which was gradual on onset, progressive associated with pain, looseness of teeth, foul taste and breath. Pain on lower back and front region of jaw which was gradual on onset, throbbing type, radiating towards ears and neck, mildly relieved on medications (painkillers), aggravated during eating. There was no history of fever, vomiting or trauma.

5. Medical History No relevant medical history.

6. Past Dental History She had undergone removal of teeth in lower right back region of jaw which was eventful (unhealed socket).

7. Personal History She consumes tobacco in chewable form since past 15 years and places it in lower right vestibular area. She brushes randomly with neem stick (twig- datun )

8. On examination

9. Extra-oral Examination Facial Symmetry: Asymmetrical S welling present over right mandibular posterior region and anterior region of around 3×3 cm in size, without any changes or ulcerations on overlying skin. TMJ: Deviated towards right on opening and closing . Non-tender Lymph Nodes: Multiple palpable right submandibular nodes, oval in shape, around 0.5-1 cm in diameter, soft, freely mobile and non-tender.

10. Intra-oral Examinations A swelling extending from distal of right mandibular canine to mesial to left mandibular 1 st premolar, of around 3×3 cm in size, without any surface changes. On palpation, it was non-tender, bony hard with egg-shell cracking present. A bony defect was present distal to right mandibular canine of around 1cm in diameter, with pus like discharge. O n palpation it was tender. A fluctuant swelling present over right alveo -lingual sulcus of around 5×1 cm in dimension with no surface alterations and was fluctuant on palpation. Generalized gingival recession present.

11. Provisional Diagnosis: Odntogenic Keratocyst on mandibular anterior region Differential Diagnosis Ameloblastoma Central Giant cell granuloma

12. Investigations Aspiration of cystic contents: Showed dirty pus colored fluid, contained shredded and fragmented cells of cystic lining. Protein analysis : Toller postulated that a protein level of less than 4.0 gm /100ml indicated a diagnosis of OKC. Radiography: OPG was advised which showed, multilocular radiolucency extending from right rams-angle region to mandibular anterior region with well defined sclerotic border without roots resorption and thinning of cortical plates and only few mm of mandibular lower border remaining.

13. Biopsy Was planned and will only provide definitive diagnosis.

14. Treatment Options: Curettage with peripheral osteotomy keeping a safety margin of 1mm Curettage followed by Chemical cauterization with carnoy’s solution Marginal mandibulectomy leaving lower border intact Segmental hemimandibulectomy with left anterior sectional mandibulectomy . Prognosis : Poor, depending upon the patient’s condition, severity of lesion and amount of mandible involved. Recurrence is most likely.

15. Odontogenic Keratocyst

16. WHO Classification of cysts of Jaws 2017 (4 th etd .)

17. 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 . 3%-11% of odontogenic cyst Classified under benign odontogenic tumors by WHO because; Behaviour : Locally destructive and high recurrence rate Histopathology : basal epithelial layer shows proliferation and budding into the underlying CT Genetics : PTCH gene mutation Possible association with Nevoid basal cell carcinoma Reclassified under developmental odontogenic cyst by WHO in 2017

18. Age : Occurs over a wide range of age groups from first to ninth decades. Bimodal distribution with peak incidence: 2 nd -3 rd decade & 5 th - later Sex : Male predilection Site : Mandible (65%)  ramus 3 rd molar area > 1 st & 2 nd molar area > anterior maxilla (25 %) In most of cases, more than one OKC are present. Clinical Features:

19. OKC grows within medullary cavity of the bone without causing obvious bone expansion in anteroposterior direction which is less compared to other cysts of comparable size. Small OKC are asymptomatic and are discovered only during radiographic examination. L arger lesions produce swellings involving the maxillary sinus and the entire ascending ramus, including the condylar and coronoid processes causing apparent facial asymmetry, pain, paraesthesia of lips and mobility of non-periodontal origin. Displacement of tooth is common that root resorption but both can occur concomittently . When maxillary anterior region is involved, tends to get infected due to vicinity to maxillary sinus.

20. OKC is associated with GORLIN-GOLTZ (NBSCS) syndrome characterized by; Basal cell carcinoma Odontogenic Keratocyst of the jaws Bifid ribs– sixth rib Plantar & palmar pits Occular hypertelorism Ectopic calcifications

21. Radiographic Features OKC demonstrate a well-defined radiolucent area with smooth and often corticated margins. Larger lesions tends to be multilocular . Sometimes associated with unerupted tooth mimicking dentigerous cyst . Root r esorption is common.

22. Radiographic classification (Toller, 1970 ) Replacemental type: develops in place of normal tooth Envelopemental type: embraces an adjacent unerupted tooth Extraneous type: develops in ascending ramus away from teeth Collateral type: adjacent to root of teeth

23. Treatment and Prognosis Enucleation with curettage Enucleation with peripheral osteotomy with safety margins. Chemical cauterization with Carnoys solution after enucleation Surgical resection of a marginal bone, part of, half of or whole mandible depending upon severity. Prognosis: Potential malignant transformation but rare Recurrence is high (15-20%)

24. Recurrence is due to; 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.