SAT-464 Management of an Aggressive Growth Hormone Producing Pituitary Macroadenoma

Objective: Acromegaly due to growth hormone (GH) producing pituitary adenoma is a complex disease. Aryl hydrocarbon receptor interacting protein (AIP) mutations cause aggressive pituitary adenomas in young patients. A study showed that AIP gene mutation analysis is positive in 11.7% of patients under 30 years with sporadic pituitary macroadenomas, and in 20% of pediatric patients. We present an aggressive GH producing pituitary adenoma in a young patient where AIP testing might be beneficial. Case presentation: 25 year old male from Ecuador presented to the hospital August 2017 with progressive vision loss over the past 2 months leading to blindness in the right eye. A brain MRI showed a large sellar/suprasellar mass with mass effect on the optic chiasm, measuring 6.7 cm, mild obstructive hydrocephalus. He had normal baseline anterior pituitary hormone work up, and normal diluted prolactin. IGF-1 was not drawn. He underwent partial tumor resection August 2017, but had large residual tumor. Pathology revealed plurihormonal pituitary adenoma.He developed secondary adrenal insufficiency requiring hydrocortisone. He was readmitted November 2017 with headaches, nausea. Head CT revealed obstructive hydrocephalus and enlarging tumor requiring craniotomy/tumor debulking with VP shunt placement. IGF-1 level: 796, with GH of 44. He underwent glucose tolerance test which did not suppress GH. He was started on IM octreotide LAR.He continued to have elevated IGF-1 of 1165, and dose increased to 30 mg Q4 weeks, then further increased to 40 mg Q4 weeks due to IGF-1 of 665. He developed severe insulin resistance, requiring 300 units of insulin per day. He was admitted June 2018 with severe metabolic acidosis in the setting of DKA, and intubated. He underwent a third craniotomy and further tumor debulking due to tumor growth after-which he developed loss of satiety control requiring restraints, causing great difficulty in diabetes control. Discussion: This is an aggressive GH producing pituitary adenoma in a young individual, on high dose octreotide LAR. A multidisciplinary approach to his care is necessary. Further surgical debulking will be necessary in his case. High dose, high frequency octreotide LAR therapy is being considered. AIP (aryl hydrocarbon receptor interacting protein) gene mutation analysis may be beneficial in this case given aggressive nature of his disease and young age. Conclusion: Pituitary adenoma causing acromegaly is a challenging disease.In young individuals, gene mutation analysis may be beneficial in order to optimize clinical genetic investigation and management. References: 1. Tichomirowa MA et al. High prevalence of AIP gene mutations following focused screening in young patients with sporadic pituitary macroadenomas. Eur J Endocrinol. 2011.