Gonadal tumor with granulosa cell tumor features in an adult testis.

Granulosa cell tumor is almost exclusively an ovarian tumor. Rare cases of granulosa cell tumor have been reported involving the testes. We report a testicular gonadal stromal tumor with granulosa cell differentiation in a 54-year-old white man. The tumor was discovered by an ultrasound evaluation for left hydrocele. The patient was clinically asymptomatic. On frozen section, the initial impression was a malignant lymphoma. Final histology on the orchiectomy specimen showed a gonadal stromal tumor with granulosa cell features. Immunohistochemical studies excluded malignant lymphoma and germ cell tumors, consistent with a stromal tumor. This case report illustrates the challenges for the pathologist in making an accurate diagnosis in unusual testicular tumors.