Alveolar soft part sarcoma: A case report and review of the literature.

Alveolar soft part sarcoma (ASPS) is a rarely diagnosed tumour of deep soft tissue origin. This tumour is more common in adolescents and young adults and has a slowly progressive clinical course, which often leads to delayed diagnosis and treatment. It is highly vascular, can be confused with other entities like haemangiomas and arteriovenous malformations clinically and radiologically and is thus challenging to report on fine needle aspiration cytology (FNAC). Diagnosing the tumour is difficult on cytology, so knowledge of this entity and the differentials with its morphological mimics on cytology is required for timely diagnosis and early management of the patient. We report a case of ASPS in a young female who presented with a large, painless swelling in the thigh, diagnosed on cytology combined with ancillary testing with immunohistochemical markers.