To explore the clinical and pathological features of rhabdomyosarcoma of the epididymis.

Three cases of epididymal rhabdomyosarcoma admitted to Shuyang People′s Hospital of Jiangsu from January 2011 to December 2019 were selected. The clinical and pathological features of the 3 cases were studied by pathological examination and immunhistochemical staining.

The 3 patients with rhabdomyosarcoma of the epididymis were aged 10 years, 23 years and 25 years, respectively. The course of disease was 1 month, 2 months and 4 months, respectively. Among them, 1 case of left epididymis and 2 cases of right epididymis, and all were single nidus. The main clinical symptom was a scrotal mass with progressive enlargement. Both ultrasonography and MRI examination showed epididymal space occupying lesions. Postoperative pathology diagnosed epididymal rhabdomyosarcoma, including 2 cases of alveolar rhabdomyosarcoma and 1 case of embryonal rhabdomyosarcoma. Microscopically, the tumor consisted of primitive mesenchymal cells and differentiated rhabdomyocytes. Immunohistochemically, the tumor cells were positive for myogenin, myogenic differentiation (MyoD1), vimentin and desmin, but negative for neuron specific enolase (NSE), S-100, actin, smooth muscle actin (SMA), CD34, CD99 and cytokeratin-pan (CKpan).

Rhabdomyosarcoma of epididymis is a rare malignant tumour, and early diagnosis and standard treatment can achieve a good prognosis.