Extraskeletal Myxoid Chondrosarcoma with Neuroendocrine Differentiation

Overview

We describe a case of extraskeletal myxoid chondrosarcoma with neuroendocrine differentiation.The tumor occurred in subcutaneous tissue of the right popliteal region in a 50-year-old man. Itmeasured 5 cm in diameter, was well circumscribed, lobular and gelatinous, and lacked anynecrosis or hemorrhage. Histologically, the tumor structure was a typical of extraskeletal myxoidchondrosarcoma. The lesion was lobulated and contained small to medium-sized chondroblast-like cells with ovoid hyperchromatic nuclei and without prominent nucleoli. The cells createdcords and nests and showed focally a perivascular rosette-like arrangement. A few of the tumorcells were spindle shaped. The myxoid matrix was stained with alcian blue and this reaction wasresistant to prior treatment with hyaluronidase. PAS-positive glycogen was found in the cyto-plasm of some tumor cells. Immunohistochemically, the tumor cells were diffusely positive forneuron specific enolase, monoclonal synaptophysin and vimentin. Following antibodies gave ne-gative results: desmin, actins, S-100 protein, pancytokeratin, epithelial membrane antigen, chro-mogranin A, neurofilament protein, myelinic basic protein, glial fibrillary acidic protein. Thepatient is well four years after the wide excision of tumor and radiotherapy. Neuroendocrinedifferentiation in extraskeletal myxoid chondrosarcoma was described at first by Chhieng et al.in 1998 ( 1 ). Our observation confirms this interesting finding.

Key words:
neuroendocrine differentiation - extraskeletal myxoid chondrosarcoma