Unveiling the uncommon: Alveolar soft part sarcoma- A case series highlighting diagnostic challenges

Alveolar soft part sarcoma (ASPS) is a rare malignant neoplasm, accounting for <1% of soft tissue sarcomas. It typically presents as a slow-growing, painless mass, most often located in the deep soft tissues of the extremities. It is frequently associated with metastatic disease at the time of diagnosis. Distinguishing ASPS from its histological mimics can be challenging, particularly when it arises in atypical locations. We present a retrospective analysis of five cases of ASPS involving uncommon sites: breast, parapharyngeal region, mandible, elbow, and thigh. Histologically, all tumors exhibited a classic alveolar architecture, characterized by nests of polygonal cells separated by delicate vascular channels. Immunohistochemistry (IHC) confirmed transcription factor E3 nuclear positivity in each case, supporting the diagnosis. Awareness of such unusual presentations is essential to avoid misdiagnosis and inappropriate management. This series underscores the importance of careful histopathological evaluation and ancillary studies in recognizing ASPS at rare anatomical sites.