SUN-289 Symptomatic Prolactinoma with Modestly Elevated Prolactin Levels: A Cautionary Tale

Introduction: Prolactinomas, although rare, are the commonest pediatric pituitary adenomas. Hyperprolactinemia in girls can cause hypogonadotropic hypogonadism, which may lead to delayed puberty, primary and secondary amenorrhea, gynecomastia and/or galactorrhea. Case Presentation: We report a case of a 15 year old girl with autism spectrum disorder who presented with irregular menses and galactorrhea for about 3-4 months. She had a BMI of 24.91 kg/m(2) and was not obese. She had menarche about 2 years ago and periods were getting increasingly irregular. She was started on oral contraceptive pills by her primary care doctor without regularization of periods. Her initial evaluation in endocrinology clinic revealed a modestly elevated prolactin level 39 ng/mL (Normal 3-18.6 ng/mL) and when repeated with dilution, it was 33 ng/mL. There was no history of nipple stimulation. Rest of pituitary function testing was within normal limits. MRI revealed a 5 x 3 mm hypo-enhancing partially cystic lesion identified within the right side of the pituitary gland with remodeling of the floor of sella turcica and deviation of the pituitary infundibulum to the left, possibly consistent with a prolactinoma. She was started on cabergoline 0.25 mg twice a week after the results of the MRI. Results: Repeat prolactin level on about 3 months of oral cabergoline was 16.5 ng/mL. There was resolution of galactorrhea. Her oral contraceptive pills were discontinued and she had spontaneous menstrual cycles after that. A repeat MRI 4 months after treatment showed decrease in size of the mass. Discussion: Symptomatic prolactinomas usually present with significant increase in prolactin levels. Also, symptoms may be difficult to identify if patient had menarche in the last 2 years. Mild elevations may be seen with stress or polycystic ovarian disease. This case highlighted significance of modestly elevated prolactin level in the setting of symptomatic prolactinomas. Conclusion: Symptomatic prolactinomas can present with modest elevations of prolactin levels. MRI pituitary should be obtained if there is strong clinical suspicion for prolactinoma. It may sometimes be difficult to assess symptoms in an adolescent girl as periods may be normally irregular for 1-2 years after menarche.