Sclerosing odontogenic carcinoma with benign fibro-osseous lesion of the mandible: an extremely rare case report.

A case of sclerosing odontogenic carcinoma (SOC) admixed with a benign fibro-osseous lesion (BFOL) is reported herein. A 67-year-old male had paresthesia in the mental region. Computed tomography detected an intragnathic mass that was focally expansile with disappearance of cortical bone, and contained admixed radiolucency and radio-opacity. Under the pathological diagnosis as benign fibro-osseous lesion, it was surgically removed by curettage. Microscopic analysis showed that a few parts of the resected materials contained dispersed thin cords and small nests of epithelial cells accompanied by fibrous stroma. Cellular atypia and mitotic figures were not evident. The diagnosis of BFOL with hyperplastic and metaplastic odontogenic epithelia was ultimately made. Eight months after the operation, the lesion recurred and segmental mandibulectomy was carried out. Histologically, the lesion was predominantly occupied by the fibro-osseous component with irregular-shaped foci of epithelial component. The epithelial component exhibited mostly thin cord or small nest patterns and showed definite perineural infiltration. Immunohistochemically, the epithelial cells were positive for p63, cytokeratin (CK) 6 and CK19, and focally positive for CK7 but negative for vimentin. MIB-1 positive nuclei were inconspicuous. To the best of our knowledge, this report is the first case of SOC with BFOL.