Alveolar soft part sarcoma of the bladder with ASPSCR1-TFE3 gene fusion as a secondary malignancy

Alveolar soft part sarcoma (ASPS) represents <1% of all soft tissue sarcomas and harbors the ASPSCR1-TFE3 translocation, which is found in pediatric renal cell carcinomas arising after chemotherapy. We present the case of a female patient, treated for metastatic retinoblastoma (Rb) with surgery, radiation, and chemotherapy at age 21 months, who was diagnosed with ASPS of the bladder 5 years later when imaging revealed a polypoid mass arising from the left bladder wall. Endoscopic biopsy and tumor resection were performed. After histopathologic confirmation of ASPSCR1-TFE3 fusion-positive ASPS, negative margins were achieved with wide local excision. At 18 months post-surgery, she remains recurrence-free.