A rare case of extraskeletal mesenchymal chondrosarcoma with dedifferentiation arising from the buccal space in a young male.

Extraskeletal mesenchymal chondrosarcoma (EMCS) is a rare and aggressive pathological variant of chondrosarcoma arising from soft tissues of mainly the extremities, meninges/dura, trunk, and orbits. EMCS comprises only 2 % of all soft tissue sarcomas and only 6 % of them arise from soft tissue in the head and neck region. It usually affects in the second and third decade of life and is common in women. It runs a very rapid clinical course with distant metastases and has poor prognosis and survival rates. Histologically it has a dimorphic presentation of small round mesenchymal cells interspersed with foci of cartilaginous differentiation. Radiographically it appears as a soft tissue lobulated mass with various patterns of calcification. This is the first case of primary and recurrent EMCS originating in the buccal space with unusual features of dedifferentiation. The diagnostic challenges in this case were the inconclusive FNAC results, lack of radiographic evidence of characteristic calcifications and presence of areas of myxoid material and dedifferentiation on histopathology. The clinical, cytological, histological, immunohistochemical, radiographic, PET-CT findings and management with review of literature is presented. The diagnostic and management pitfalls of this extremely rare tumor are also discussed.