CLINICAL NOTES: Cystic lesion L mandible - ?KCOT.

The lesion appeared unicystic both radiologically and at the time of surgery.


"Left marsupialization plus tooth": The specimen comprises three teeth and fragments of tan soft tissue measuring in aggregate 25x25x3mm. All soft tissue is submitted for histological examination. P1. (MAS)

MICROSCOPIC DESCRIPTION: Sections show fragments of trabecular bone and adjacent fibrous tissue. Within the fibrous tissue there is an ameloblastoma comprising fragments of a peripherally pallisaded and focally basaloid appearing epithelial lining of columnar cells with hyperchromatic nuclei with focal areas demonstrating reverse polarity along the basal layer of epithelium. There are numerous invaginations of epithelium into the fibrous wall of this fragmented cystic tumour, but there are no unequivocal separate nests or groups of epithelium within this fibrous stroma (see comment). Centrally within the invaginations and superfically in the epithelial lining there is stellate reticulum which shows multiple areas of squamous metaplasia. There is no invasion of bone by tumour. Comment: Due to the fragmented nature of the specimen, assessment of the invaginations of the epithlium into the fibrous wall of the tumour is difficult, however the separate nests are favoured to be cross cut sections of invaginations of the epithelium into the fibrous. The appearances are consistent with the unilocular luminal type of ameloblastoma.

DIAGNOSIS: Left marsupialization plus tooth: Ameloblastoma; favoured to be unicystic luminal type.