Keratocystic tumor of mandible

Case contributed by Oliver Hennessy
Diagnosis certain


Jaw pain

Patient Data

Age: 23
Gender: Male

There is a lytic benign appearing lesion within the angle of the mandible on the right. There is well-defined sclerotic margin in its outline with no cortical breach and no soft tissue mass.

There is no involvement of the adjacent dental anatomy. There is no unerupted tooth associated with this mandibular cystic lesion. 

The appearances are those of a benign lesion, probably a keratocystic odontogenic tumor.


There is a unilocular lytic lesion in the angle of the right hemimandible extending anteriorly from the lateral root of the second molar to the ascending ramus of the mandible posteriorly. The inferior alveolar nerve canal courses along the posterior aspect of the lesion with focal area of dehiscence of the canal; it then courses inferior to the canal in the body of the mandible. The internal attenuation is noted of the fluid attenuation. There is no pathological fracture, periosteal reaction or extraosseous tissue extension.

Unremarkable appearance of the the reminder of the mandible with enlocated temporomandibular joints. The imaged paranasal sinuses are clear.


There is a unilocular lytic lesion in the right mandibular angle with imaging appearances of either keratocystic odontogenic tumor or a unilocular ameloblastoma


Right mandibular radiolucency for investigation ?keratocyst. -> specimen is lining/wall of cyst.

MACROSCOPIC DESCRIPTION: "Right mandibular ramus cyst": An irregular strip of tan and dark red tissue 35x7x3mm. 6xTS. A1. (SK)

MICROSCOPIC DESCRIPTION: Sections show strips of cyst wall with fibrous stroma. The cyst is lined by stratified squamous epithelium 5-10 cells thick, with an undulating surface and a basal layer with palisading. There are scattered mitoses, however nuclear atypia is not seen. Several areas of ulceration with granulation tissue and acute inflammation are present. The stroma contains a scattered moderate infiltrate of lymphocytes, plasma cells and occasional eosinophils and neutrophils. No daughter cysts or features of ameloblastoma are seen. There is no evidence of dysplasia or malignancy.

DIAGNOSIS: Right mandibular ramus cyst: Keratocystic odontogenic tumor (KCOT).

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