Extratesticular Leydig cell tumor next to the left testis: a case report and literature review

Background: Extratesticular Leydig cell tumor is a relatively rare kind of tumor, especially involving the testis. Case presentation: We report a case of a 7-year-old boy with extratesticular Leydig cell tumor next to the testis. An intraoperative biopsy revealed that a painless mass was presented in the left scrotum. The ultrasonography identified the left varicocele and an enlarged left testis with uneven echoes. The patient underwent left radical orchiectomy. The mass, 2.5 x 2.5 x 2 cm in size, was located next to the left testis. Immunohistochemical analysis was carried out and indicated that the tumor cells were positive for vimentin, inhibin, syn and Ki-67, and were negative for S-100, cgA and CD99. The pathologic diagnosis was considered as a benign extratesticular Leydig cell tumor. Conclusions: We reported an extratesticular Leydig cell tumor next to the testis, and vimentin, inhibin, syn and Ki-67 might be regarded as positive medicines for the treatment.