SAT-209 Treatment-Resistant Hypertension in a Post-Transplant Patient with Cystic Fibrosis: A Rare Case of Pheochromocytoma

Background: Pheochromocytoma is a rare catecholamine-producing tumor with an estimated incidence of less than 0.1% in the global population. We present the case of a pheochromocytoma in a 25-year-old man with a background history of a double-lung transplant for Cystic Fibrosis, carried out 5 years earlier. Clinical Case: A 25 year old, with a background history of Cystic Fibrosis and a Double Lung transplant in 2012 presented to the emergency department with crampy abdominal pain, nausea and vomiting. He was diagnosed with Distal Intestinal Obstruction syndrome (DIOS) for which he was admitted for rehydration and laxatives. Contrast-enhanced computed tomography (CT) imaging of the abdomen and pelvis which showed a 3.4 cm right adrenal lesion, which was confirmed by a subsequent MRI Adrenals and an Endocrinology review was requested. On review, the patient was noted to be hypertensive with a blood pressure averaging 170/90 despite treatment with 3 different anti-hypertensive medications - namely amlodipine, telmisartan and doxazosin. On review of his medical notes, it was clear that he had been persistently hypertensive over the last 3 years. On further questioning, he noted increasingly frequent sweating episodes over the last number of months but denied any palpitations, headache or back pain. Laboratory analysis showed an elevated plasma normetanephrines (NMN) of 3167 pmol/L (182-867) as well as elevated metanephrines (MN) of 793 pmol/L (61-377) and high 3-MT of 257 pmol/L (<185). His MIBG scan showed only a mild increase in the uptake of tracer to the right adrenal gland compared to the left. The case was discussed at a multidisciplinary meeting and given the suggestive laboratory and radiologic findings, a presumptive diagnosis of pheochromocytoma was made. After controlling blood pressure with an alpha-blocker and beta-blocker for a week, the patient was hydrated and scheduled for an elective right adrenalectomy. The histopathology of the excised adrenal gland was consistent with a 3cm pheochromocytoma with none of the adverse features associated with malignant potential. The patient recovered well post-op, his blood pressure normalised and he was discharged home well for follow-up at the Endocrine and Transplant clinics. Conclusion: We describe a rare case of a right adrenal pheochromocytoma in a young man with multiple co-morbidities, who completely recovered after tumor resection. This case highlights the crucial importance of investigating secondary causes of hypertension, especially in younger patients. This is the first documented case in the literature of a case of pheochromocytoma in a post-transplant patient with Cystic Fibrosis. References: 1. Farrugia FA, Marikos G et al. Pheochromocytoma, diagnosis and treatment: Review of the literature. Endocrine Regulation, Volume 51, Issue 3, 30th August 2017.