Isolated luteinizing hormone (LH) elevation in a woman with secondary amenorrhea: a clue to the diagnosis of an inhibin B–producing thecoma and insights into the influence of inhibin B on LH

Objective

To review the diagnostic possibilities that exists when the workup of amenorrhea reveals an isolated LH elevation; and to examine the effect of inhibin B on LH levels in vivo.

Design

Case report.

Setting

University hospital.

Patient(s)

A 20-year-old woman presented with secondary amenorrhea. Her FSH measurement was low, and the LH level was elevated. The recognition that this was an unusual pattern led to the diagnosis of a rare but very treatable inhibin B–producing thecoma, despite the fact that results on the initial pelvic ultrasound examination performed 10 months after presentation of amenorrhea were relatively unremarkable.

Intervention(s)

Surgical removal of an ovarian thecoma.

Main Outcome Measure(s)

Gonadotropins, E₂, inhibin B, menstrual bleeding, and fertility.

Result(s)

Removal of the ovarian thecoma resulted in a normalization of FSH, LH, and inhibin B levels and a return of spontaneous menses 28 days later. Pregnancy occurred with the third postoperative menstrual cycle, followed by the delivery of a healthy full-term girl.

Conclusion(s)

Inhibin B–producing sex cord granolosa–stromal cell tumors should be considered in women who present with amenorrhea with isolated LH elevations, even in the setting of a previously normal pelvic ultrasound report. Diagnostic considerations that arise in the workup of amenorrhea when there is an isolated elevation in LH that is accompanied by normal or low FSH levels are reviewed. This rare clinical presentation provides the opportunity to observe the impact of inhibin B on gonadotropins in vivo.

Key Words: Isolated LH elevation, inhibin B, thecoma, amenorrhea