OBJECTIVE To describe an unusual presentation of a follicle-stimulating hormone-secreting pituitary adenoma leading to ovarian hyperstimulation syndrome. We also discuss the pathophysiology and subsequent management of these tumors. METHODS This is a case report and review of the literature. A 37-year-old female with menorrhagia was found to have bilateral multilocular adnexal cysts with concern for ovarian hyperstimulation syndrome. RESULTS Labs revealed elevated follicle-stimulating hormone, and an eminent estradiol level. Pituitary magnetic resonance imaging revealed a macroadenoma with cavernous sinus invasion. The patient went on to have a successful transsphenoidal resection with normalization of hormones and subsequent resumption of menstrual cycles. CONCLUSIONS With the help of this case report, we illustrate the pathogenesis of functioning gonadotroph adenomas as well as the management challenges associated with these tumors. Our case is unique in its presentation with severe hyperestrogenemia and cavernous sinus invasion pointing towards a clinically aggressive adenoma. It is important to increase awareness of these tumors to ensure timely and effective management of their complications.