Nonfunctioning pituitary macroadenoma presenting with mild hyperprolactinemia and amenorrhea

Abstract Objective: To describe a patient with a clinically nonfunctioning pituitary macroadenoma who presented with mild hyperprolactinemia and amenorrhea. Design: Case report. Setting: Tertiary care medical facility. Patient(s): A 44-year-old woman with a 6-month history of amenorrhea. Intervention(s): Pituitary testing, magnetic resonance imaging of the sella turcica, and transsphenoidal surgery. Main Outcome Measure(s): Pituitary function testing, magnetic resonance imaging, and return of menstrual cycles. Result(s): Baseline laboratory data revealed a serum prolactin level of 34 ng/mL (normal range, 3–20 ng/mL), normal thyroid function test results, and an FSH level of 6.7 mIU/mL. A second fasting prolactin level was 48 ng/mL. Magnetic resonance imaging of the sella turcica revealed a pituitary macroadenoma measuring 1.4 × 3.2 cm. Further testing of baseline pituitary function revealed normal findings. The patient underwent an uncomplicated transsphenoidal resection of the pituitary tumor and maintained normal pituitary function. Pathologic evaluation revealed a pituitary adenoma that stained positive for FSH and focally for the α subunit. The adenoma stained negative for GH, prolactin, ACTH, LH, and TSH. Conclusion(s): This patient had a nonsecreting gonadotroph macroadenoma that resulted in hypogonadotropic hypogonadism along with mild hyperprolactinemia, presumably secondary to interruption of normal transport down the pituitary stalk.