Clinical presentation of alveolar soft-part sarcoma.

Alveolar soft-part sarcomas are rare and seldom considered in the differential diagnosis of a soft-tissue mass. Thus, early clinical recognition can be elusive. The authors have identified several clinical and radiographic features of alveolar soft-part sarcoma, emphasizing the importance of magnetic resonance imaging in the preoperative diagnostic and staging workup. Accurate diagnosis and treatment of this unusual tumor requires clinical suspicion and clinicopathologic correlation with appropriate radiographic studies. If the clinical or radiographic interpretation is equivocal, early biopsy is essential to differentiate alveolar soft-part sarcoma from arteriovenous malformation.