[The histogenesis of alveolar soft part sarcoma: a clinicopathological analysis of 135 cases].

135 cases of alveolar soft part sarcoma (ASPS) are presented. It is the largest series of ASPS currently reported in the medical literature. Follow-up clinical data were available in 51 cases. 68 of the patients were male and 67 were female. The mean age of the patients when making the diagnosis was 35.5 years. Most of the tumors were located at the extremities (72.1%), particularly on the thigh and buttock (36.1%). The five year survival rate was 45.9%, the recurrence rate was 47.1%, and the metastatic rate was 35.3%. The most common sites of metastases were the lung, brain and liver. Microscopially, all the tumors gave a typical organoid structure. Electron microscopic study showed special crystals in the tumor cells. 33 cases of ASPS were examined immunohistochemically with 16 kinds of antibodies in order to clarify the histogenesis of alveolar soft part sarcoma. The presence of desmin, actin, myoglobin and myosin suggests the myogenic character of this tumor.