An extremely rare case of pituitary functioning gonadotroph microadenoma accompanied by ovarian hyperstimulation syndrome in a woman of reproductive age

OBJECTIVE: To report a case of pituitary functioning gonadotroph microadenoma accompanied by ovarian hyperstimulation syndrome (OHSS) in a woman of reproductive age. DESIGN: A case report. SETTING: Tertiary care unit of a university hospital. PATIENTS: A 42-year-old parous woman with bilateral ovarian enlargement presumed to be secondary to a functioning gonadotroph pituitary microadenoma. INTERVENTIONS: Oral contraceptives and endoscopic transsphenoidal surgery for adenoma that initially could not be visualized on a magnetic resonance imaging (MRI) scan. MAIN OUTCOME MEASURES: Medical and radiographic assessment of endogenously induced OHSS and its resolution after treatment. RESULTS: The patient was diagnosed with OHSS secondary to elevations in endogenous levels of follicle-stimulating hormone (FSH). The cranial contrast-enhanced MRI scan did not show any apparent tumor in the pituitary gland. She was, therefore, treated with oral contraceptives, which resulted in a modest resolution of ovarian enlargement; however, this treatment became ineffective 3 years later. A small pituitary adenoma (maximum diameter of 8 mm) was suspected on repeated MRI (2 years after the first MRI). Selective adenomectomy was performed, which resulted in normalization of the ovarian size and resumption of regular menstrual cycles. CONCLUSIONS: We report a case of a functional pituitary microadenoma secreting FSH in quantities significant enough to result in OHSS. The excessive FSH production was resistant to medical therapy; however, surgical treatment was ultimately successful.