Primitive Ewing Sarcoma of Epididymis: A Case Report and Literature Review.

We present the case of a 22-year-old man with a firm and tender mass in the left scrotum region. Color Doppler ultrasound and radiographic examination (CT and MRI) suggested that the mass arose from the left epididymis without tumor metastasis. The histopathological and immunohistochemical findings revealed a chrysanthemum-like arrangement of round tumor cells, along with strong positive expression of CD99, vimentin, CD117, CD56, and Ki-67 (70%), supporting the diagnosis of primary epididymal Ewing sarcoma. The patient underwent surgical excision and received 3 cycles of postoperative chemotherapy with vincristine, doxorubicin, and cyclophosphamide. The patient is recovering satisfactorily, and his follow-up treatments and condition are being monitored.