A Leydig Cell Tumor of the Ovary Resulting in Extreme Hyperandrogenism, Erythrocytosis, and Recurrent Pulmonary Embolism

Context: Secondary erythrocytosis due to androgens is most commonly seen in the context of T replacement therapy in men. Leydig cell ovarian tumors are a rare cause of virilization, erythrocytosis, and thromboembolism. Patient Case: We describe the case of a 55-year-old postmenopausal woman who presented with a 3-year history of frontal balding and virilization and a 5-year history of obstructive sleep apnea. She had not experienced significant alteration in libido or mood. Menstruation had ceased at age 46. She had a history of recurrent pulmonary embolism and unexplained secondary erythrocytosis. Past hematological investigations had not revealed any evidence of malignancy or thrombophilia, and the JAK2 mutation was negative. The serum erythropoietin was mildly elevated at 20.3 mIU/mL (normal range, 3.6–16.6 mIU/mL). The serum T was initially reported (by immunoassays) as >1600 ng/dL (>55 nmol/L). Similarly, serum androstenedione (>1000 ng/dL; >35 nmol/L), estradiol (169 pg/mL; 621 pmol/L), and dehydroe...