Secondary amenorrhea and infertility caused by an inhibin-B-producing ovarian fibrothecoma.

Objective: To report a case of secondary amenorrhea and infertility caused by an inhibin-B-producing ovarian fibrothecoma.

Design: Case report.

Setting: Academic medical center.

Patient: A 37-year-old woman with a 2-year history of secondary amenorrhea and infertility.

Intervention(s): Operative removal of a 5-cm ovarian fibrothecoma.

Main Outcome Measure(s): Luteinizing hormone, FSH, E2, inhibin-B, TSH, and prolactin measured preoperatively and postoperatively. Immunostaining of tumor cells for inhibin and LH.

Result(s): Preoperative hormone levels were as follows: FSH, 1.7 mIU/mL; LH, 23.4 mIU/mL; E2, 31 pg/mL; and inhibin B, 1,154 pg/mL. Three weeks postoperatively, the FSH was 1.5 mIU/mL, LH decreased to 7.1 mIU/mL, E2 increased to 276 pg/mL, and inhibin-B decreased to 17 pg/mL. The fibrothecoma did not stain for LH but was strongly positive for inhibin. Regular menstrual cycles resumed 28 days postoperatively.

Conclusion(s): Inhibin-B produced by an ovarian tumor profoundly suppressed FSH levels and resulted in secondary amenorrhea and infertility. Use of sensitive and specific immunoassays for inhibin-A and -B may aid in the differential diagnosis of hormonally active ovarian tumors.