Rare case of occult testosterone‐producing ovarian tumor that was diagnosed by selective venous hormone sampling

CASE: A 32 year old woman was referred because of secondary amenorrhea, hirsutism, and voice deepening. OUTCOME: The blood testosterone level was markedly high. A transvaginal ultrasound revealed a small region in the left ovary, but whether or not it was a tumor was unclear. Therefore, selective ovarian venous sampling was performed. Consequently, the testosterone level was selectively increased in a blood sample that was taken from the left ovarian vein, the tumor was successfully localized, and a laparoscopic left oophorectomy was performed. Although the left ovary appeared to be normal at laparoscopy, the androgen‐secreting tumor was located within it. The tumor was diagnosed as a Leydig cell tumor by histopathological analyses. CONCLUSION: This report demonstrates that selective blood sampling from ovarian veins before an operation is effective in localizing an androgen‐producing ovarian tumor that is difficult to diagnose by imaging studies.