Amenorrhea as a presentation of Cushing's syndrome.

Summary: Menstrual cycle abnormalities are common in premenopausal females with Cushing's syndrome, although the underlying mechanism is poorly understood. Signs and symptoms found in Cushing's syndrome overlap with polycystic ovarian syndrome (PCOS). The patient is a 33-year-old female previously diagnosed by a gynecologist with PCOS and treated with oral contraceptive pills (OCPs) for 2 years. She then discontinued her OCPs without consulting a clinician, resulting in amenorrhea for 6 months, for which she presented. She also had symptoms of depression and anxiety but had no other signs and symptoms of Cushing's syndrome, except a plethoric face. Initial lab work showed evidence of central hypogonadism (low luteinizing hormone, follicle-stimulating hormone, and estrogen), so a complete anterior pituitary hormone workup was done. Her thyroid-stimulating hormone was also low with a low free T4 level. Prolactin level was normal, but surprisingly, her AM cortisol level was high. The Cushing's syndrome workup revealed non-suppressed cortisol after a 1 mg dexamethasone suppression test and positive 24-h urine cortisol with suppressed adrenocorticotrophic hormone. A CT scan of her adrenal glands revealed a left adrenal adenoma. She underwent a left adrenalectomy, after which her menstrual cycles became regular again, and pituitary function has recovered.

Learning points: In Cushing's syndrome, female patients can have menstrual abnormalities due to the high cortisol levels, which can affect gonadotrophin levels. We encourage clinicians to include Cushing's syndrome in the differential diagnosis of patients with central hypogonadism.