Functioning gonadotroph macroadenoma associated with multiple endocrine neoplasia type 1.

We report the case of a 35-year-old woman with clinically and genetically confirmed multiple endocrine neoplasia type 1 (MEN1) who presented with abnormal uterine bleeding, hypermenorrhea, menstrual irregularities, and visual field defects. Hormonal evaluation revealed elevated estradiol levels, non-suppressed follicle-stimulating hormone (FSH), suppressed luteinizing hormone (LH), and mild hyperprolactinemia. Magnetic resonance imaging demonstrated a large pituitary macroadenoma. The patient underwent transsphenoidal surgery, and histopathological and immunohistochemical (IHQ) analyses confirmed a functioning gonadotroph adenoma. Postoperatively, clinical and gynecologic symptoms improved; however, residual tumor tissue showed progression on follow-up imaging. This case highlights a rare but clinically significant manifestation of MEN1-associated pituitary disease. Functioning gonadotroph adenomas may present with ovarian hyperstimulation rather than typical hypogonadism or mass-related symptoms. Recognition of this distinct biochemical and clinical profile is essential for timely diagnosis and management. Functioning gonadotroph adenomas, although rare in MEN1, should be considered in patients presenting with ovarian hyperstimulation and atypical gynecologic symptoms. Surgical resection is the mainstay of treatment, but long-term surveillance is required due to the risk of residual disease progression.