Alveolar soft part sarcoma of the pararectal space in the pelvic cavity: a case report and review of the literature

Alveolar soft part sarcoma is an extremely rare type of soft tissue malignancy, manifests in a variety of locations. We report a case of a 28-year-old Chinese woman presented with alveolar soft part sarcoma. To the best of our knowledge, this study is the first to report a case of alveolar soft part sarcoma with primary location in the pararectal space of the pelvic cavity. Histopathologically, the tumor presented as relatively uniform, organoid, with an alveolar or nest-like growth pattern that varied in size and shape. Immunohistochemical examination revealed expression of TFE3 (transcription factor E3), S-100, and Vimentin. The case exhibited typical histological and immunohistochemical features are suggestive of alveolar soft part sarcoma. After surgical resection, no evidence of local recurrence or distant metastasis was observed after complete resection in this patient in the five months of follow-up.