A premenopausal woman with virilization secondary to an ovarian Leydig cell tumor.

Background: A 33-year-old woman presented to an endocrinology clinic with a 5-year history of secondary amenorrhea. 2 years before presentation, she had noticed progressively worsening signs of virilization.

Investigations: Measurement of levels of serum free and total testosterone, androstenedione, dehydroepiandrosterone sulfate and gonadotropins; transvaginal ultrasonography, abdominal and pelvic MRI and (18)F-fluorodeoxyglucose PET imaging.

Diagnosis: Virilization secondary to an ovarian Leydig cell tumor.

Management: The patient underwent a left salpingo-oophorectomy that confirmed the diagnosis of a unilateral Leydig cell tumor. Complete normalization of androgens and gonadotropin levels was achieved after surgery.