[Primitive neuroectodermal tumor/Ewing's sarcoma of the penis in children: a case report and review of the literature].

OBJECTIVE: To investigate the clinical manifestations, pathological characteristics and treatment of primitive neuroectodermal tumor/Ewing's sarcoma (PNET/EWS) of the penis in children. METHODS: We analyzed the clinical data of a case of PNET/EWS and reviewed relevant literature. RESULTS: The patient was a 5-year-old boy, admitted for penis swelling with pain for 11 months. Biopsy showed a small round cell tumor, CD99 positive by immunohistochemical staining, with EWS translocation by fluorescence in situ hybridization on molecular biological examination. The tumor was confirmed to be PNET/EWS of the penis, and disappeared after 45 weeks of chemotherapy and local radiotherapy. CONCLUSION: PNET/EWS of the penis is an extremely rare disease, with no specific clinical symptoms except penis enlargement with pain. Immunohistochemistry and molecular biological examination contribute to its diagnosis.