SUN-291 17 Year Old Male with Galactorrhea and Elevations in Prolactin and ACTH in the Setting of a Pituitary Microadenoma

Pituitary adenomas are uncommon in children with an incidence of 0.1 per million. Prolactinomas are the most frequent, followed by ACTH-secreting adenomas, whereas TSH-, GH- and non-functioning adenomas are less frequently encountered. Plurihormonal pituitary adenomas, though extremely rare have also been reported, with ACTH/Prolactin and ACTH/GH being the most common. (Lubov B. Mitrofanova, 2017) A 17 year old male presented with bilateral ‘milky’ areolar discharge for the past 2 weeks. He also had a history of chronic headaches and decreased energy for the past 6 months. Initial evaluation at his PCP’s office showed an elevated prolactin of 90.2 ng/mL (4.0-15.2) and normal TSH and free T4. At presentation to endocrinology, physical exam showed weight of 106.8 kg >99%ile, height of 182.8 cm, 85%ile, BMI of 32, 98%ile, and blood pressures 117/50 mmHg, 50(th)/10(th)%ile respectively. He was also noted to have circumferential acanthosis nigricans of the neck, gynecomastia, Tanner V pubic hair, and 20 mL testes bilaterally; no striae, nuchal adiposity or areolar discharge was noted. Subsequent biochemical testing at 0900 showed prolactin, 100.7 ng/mL (4.0-15.2), ACTH, 177 pg/mL (<47), cortisol, 21.6 ug/dL (5.3-22.5), FSH 0.8 mU/mL (1.5-12.4), LH 1.5 mU/mL (1.8-10.8), with T4, TSH and IGF-1 within normal limits. An MRI of the brain showed a 3 mm microadenoma in the adenohypophysis. Given elevated prolactin, ACTH and high normal morning cortisol, there were concerns for Cushing’s disease, and midnight salivary cortisols were obtained, which were normal: 0.033, 0.036 and 0.040 ug/dL (<0.259). He was then started on cabergoline, titrated up to 0.5 mg twice a week. After 3 months, he had resolution of the areolar discharge and a decrease in headache frequency as well as improved energy. His repeat labs showed prolactin, 8.4 ng/mL, AM cortisol 17.4 ng/mL, though ACTH was quantity not sufficient. Hyperprolactinemia is most commonly caused by a pituitary adenoma, and symptoms in men include gynecomastia, areolar discharge, fatigue and decreased libido. Plurihormonal adenomas, though a rarity, must be considered when an adenoma is confirmed by imaging, and should trigger screening for other pituitary hormonal abnormalities. Treatment with D2-receptor agonists has been shown to be an effective treatment for some plurihormonal adenomas, likely dependent on D2 receptor expression of the particular adenoma in question (Shalini Kunasegaran, 2017). Lubov B. Mitrofanova, P. V. (2017). Plurihormonal cells of normal anterior pituitary: Facts and conclusions. Oncotarget, 8(17): 29282-29299. Shalini Kunasegaran, M. S. (2017). An unusual case of Cushing's syndrome due to bihormonal ACTH-prolactin secreting pituitary macroadenoma with rapid response to cabergoline. BMJ Case Reports, 10.1136/bcr-2017-219921 .