[Alveolar soft part sarcomas. Apropos of 6 cases and review of the literature].

This is a clinicopathologic study of 6 cases of alveolar soft-part sarcoma. The patients age ranges from 8 to 47 years. All patients are women. In 5 cases the localization of the primary tumor is the lower extremities. Histologically the tumors have a distinctive organoid pattern outlined by thin-walled capillaries and are composed of nests of large polyhedral cells with abundant finely granular, acidophilic cytoplasm. Two tumors, among the 4 tested cases, have cytoplasmic PAS positive diastase-resistant crystalline structures. Electron microscopic study of one tumor shows intracytoplasmic glycogen, small membrane-bound electron-dense granules, Golgi lamellae and crystalline structures. Immunoperoxidase study performed in one case reveals a positivity with antikeratin and anti-enolase (NSE) antibodies. The prognosis of this tumor is poor. The main metastasis are in the lung and in the brain. Often the patients develop metastasis before detection of the primary tumor. The histogenesis of alveolar soft part sarcoma and the identity of the characteristic crystalloids remain open for discussion.