Mesenchymal chondrosarcoma--a case report with an ultrastructural study and review of Japanese literatures.

A case of mesenchymal chondrosarcoma occurring in the left maxilla of a 30-year-old Japanese male was reported. Electron microscopic observation confirmed transition of undifferentiated cells to chondrocytes and calcification in similar manner as previously described with physiological processes. Matrix vesicles were thought to be the cytoplasmic products of tumor chondrocytes. Electron-dense finely granular deposits resembling the organic matrix of cartilagenous calcification were seen within the intercellular matrix. Matrix vesicles were also closely related to these deposits. Japanese cases of this rare tumor were reviewed and 8 cases, including the present case as 6th among them, were accepted. Clinical characteristics were similar to those of a series reported by SALVADOR et al.