Alveolar soft part sarcoma: A case report with emphasis on some unusual cytological features

Alveolar soft part sarcoma is a very rare, slow growing highly angiogenic tumor with poor prognosis. Most common site in children and infants is head and neck region and in adults it most commonly occurs in extremities especially thigh. In our case study, an 8 years old female patient presented with a gradually progressive left shoulder lump. FNAC from the lesion showed cellular smears with polyhedral and spindly cells showing abundant finely vacuolated cytoplasm, nuclear pleomorphism, intranuclear pseudoinclusions, and few bare nuclei. Perivascular arrangement of cells was peculiar in addition to the presence of intracytoplasmic metachromatic PAS positive diastase resistant granules. A presumptive diagnosis of alveolar soft part sarcoma with differentials of granular cell tumor and PEComa was considered and the lesion was excised. Although the histopathological features were not characteristic (ie, showing mainly solid pattern without classic alveolar pattern), immunohistochemistry were diagnostic (negative for S 100, Desmin, Cytokeratin, EMA, and moderate to strong nuclear positivity for TFE3). Thus, the diagnosis of alveolar soft part sarcoma was established. This case is being presented for its rarity and unique cytological and histopathological features.