Alveolar soft part sarcoma occurring in the penis of a 3-year-old boy

RATIONALE Alveolar soft part sarcoma (ASPS) is a rare, malignant neoplasm, which mostly occurs in the upper and lower extremities. This article presents an unusual case of ASPS involving the penis of a 3-year-old boy. To our knowledge, this is the first case of ASPS in the penis of a child. PATIENT CONCERNS The patient complained of slight penile pain for 1 year and a soft tissue mass could be palpated in his penis. DIAGNOSES Imaging was performed on the penis. The pathological feature of the mass was evaluated through biopsy examination. It was found that the mass was an alveolar soft tissue sarcoma, which was then confirmed by immunohistochemistry. INTERVENTIONS The patient only underwent a partial penectomy because his parents wished to keep the penis. Conventional chemotherapy has been performed for 6 months after the surgery. OUTCOMES At 28-month follow-up the mass did not increase apparently, and no signs of metastasis were found. LESSONS ASPS may occur originally in the penis.