Alveolar soft part sarcoma presenting as asymptomatic pulmonary nodules: report of a case with ultrastructural diagnosis.

Lung metastases are frequently the mode of presentation of alveolar soft part sarcoma,' a rare tumour of the skeletal muscles of the thigh and arm occurring between the ages of about 20 and 30 years, with a female predominance.2 Although the pathological features of this tumour are fairly characteristic, it is the demonstration by electron microscopy of typical intracellular crystals that is pathognomonic.34 We report a case of alveolar soft part sarcoma presenting as asymptomatic pulmonary nodules, without evidence of a primary tumour, in which the diagnosis was established by electron microscopy of material obtained by lung biopsy.