ODP286 A Case of Synchronous Growth Hormone and Adrenocorticotrophic Hormone Secretion in a Patient with an Incidental Pituitary Adenoma.

The most common type of co-secreting functional pituitary adenoma is a tumor-producing growth hormone and prolactin. Other types of co-existing functioning adenomas are extremely rare. We present a 68-year-old male patient with a pituitary adenoma presenting with acromegaly and Cushing's disease (CD). A 68-year-old male was referred for an incidental pituitary macroadenoma found on magnetic resonance imaging (MRI) for his chronic nasal congestion. He denied headaches or blurry vision. He reported an increase in shoe size, worsening hypertension and diabetes, and a 40-pounds weight gain over several years. Past medical history included arthritis, type two diabetes mellitus, hypertension, sleep apnea, hypogonadism, chronic kidney disease, and coronary artery disease. Physical exam was notable for BMI of 51 kg/m(2) and enlarged hands and feet. No stigmata of Cushing's syndrome were present. MRI showed a 2. 0×2.5 cm sellar mass involving the right cavernous sinus without a mass effect on the optic chiasm. Laboratory workup showed an elevated IGF-1 level of 703 ng/mL and 678 on repeat, growth hormone (GH) 1.1 ng/mL, adrenocorticotropic hormone (ACTH) 41 pg/mL, and am cortisol 15 mcg/dL. Am cortisol after 1 mg of dexamethasone was 6.2 mcg/dL with an appropriate dexamethasone level. His and 24-hour urine-free cortisol was elevated at 87.1 mcg/24h, HgbA1C was 8.3%, testosterone level was low, and PRL and thyroid levels were normal. He underwent transsphenoidal surgery (TSS). Postoperative morning cortisol day 1 was 18.9 mcg/dL. Pathology showed a sparsely granulated somatotroph adenoma. Seven days post-surgery, he presented with diplopia, ophthalmoplegia, and ptosis. MRI showed enlargement of the right cavernous sinus with possible residual tumor and blood products. He underwent a second TSS with evacuation of a hematoma. The patient's nadir postoperative serum cortisol was 14.4 mcg/dL and IGF-1 level 513 ng/mL one month after his initial surgery. Pathology showed organizing hemorrhage and necrotic pituitary adenoma. His ophthalmoplegia resolved, and diplopia partially improved. The synchronous occurrence of CD and acromegaly is an extremely rare condition. It can be secondary to either a plurihormonal adenoma or two functional adenomas. In our case, the pathology findings suggest double adenomas. Surgical resection is first-line therapy for acromegaly and CD. Stereotactic radiosurgery and medical therapy are second-line options in persistent disease. The 5-year remission rates with Gamma Knife radiosurgery are higher in CD (81%) as compared to acromegaly. 1 Pasireotide, a somatostatin receptor ligand approved for both CD and acromegaly. Worsening glycemic control is a significant challenging aspect of its use. Presentation: No date and time listed