Since Pick,1 in 1905, first described a tumor of the ovary closely resembling the seminiferous tubules of the testis, others, usually of more atypical structure, have been described. These growths are made up of apparently masculine tissue and influence the secondary sex characteristics in a masculine direction; but, strangely, those with the least microscopic resemblance to testis show the greatest masculinizing effect. The tumor is mildly malignant, and direct extension occurs, although true metastasis has not been reported. Originally called adenoma testiculare ovarii, it has more recently been designated arrhenoblastoma, from the Greek arrhen, meaning male.
The arrhenoblastoma was thought by Meyer2 to arise from certain embryonic remains incorporated in the ovarian medulla, and he considered the microscopic appearance of the tissue to be characteristic. Novak and Long3 recently discussed this type of tumor together with the more frequent feminizing granulosa cell tumor; they found twenty-eight cases