MON-390 Giant Cystic Adrenal Incidentaloma in Pregnancy: A Case Report

Introduction Adrenal incidentalomas in pregnancy are extremely rare but can be very dangerous. Management of such incidentalomas in pregnancy are not clearly defined, and published literature mostly consists of case reports. Clinical Case A 29-year-old female presented with severe right-sided flank pain. She was 15 weeks pregnant and had completed her first pregnancy 18 months ago without complications. In 2012 she presented with similar symptoms and had a CT KUB which showed a right renal stone in the proximal ureter and underwent stenting. A right-sided adrenal incidentaloma in the size of 4cm x 4.5cm x 3.9cm with 19HU (Hounsfield Units) was also detected and was not further evaluated. She did not have a family history of malignancy and was not on regular medication. Her routine observations were normal with a blood pressure of 110/70mmHg. The examination was unremarkable apart from right-sided flank tenderness. Routine biochemistry was normal. An ultrasound of the abdomen showed a sizeable adrenal cyst which has significantly increased in size (now 900cc, previously 312cc). An abdominal MRI revealed a 13 x 12 x 12 cm right-sided adrenal mass which is heterogeneous with a multi-loculated haemorrhagic component. The mass appeared well capsulated with compression of the inferior vena cava and displacing the right kidney. There was no apparent invasion into adjacent structures. A morning cortisol was 401nmol/l (no reference range) with ACTH 1.7pmol/L (no reference range) and plasma metanephrines were 98pmol/L (<447pmol/L). However, normetanephrine was elevated at 961pmol/L (<590pmol/L) with repeat levels at 1196pmol/L, raising concerns of a possible cystic phaeochromocytoma. Appropriateness for surgery discussed in an MDT meeting comprise of endocrinologists, obstetrician and endocrinology surgeon. The patient herself was not keen for surgery, and we decided on close observation with monthly repeat catecholamine levels and ultrasound scans. The patient remained asymptomatic with normal blood pressure. Repeat plasma Metanephrines (25/05/2018- 85pmol/L , 22/08/2018- 75pmol/L), Normetanephrine (25/05/2018- 410pmol/L, 22/08/2018- 410pmol/L) and plasma 3-Methoxytyramine (25/05/2018- <50pmol/L, 22/08/2018- <50pmol/L) were all normal. A repeat ultrasound confirmed reduced mass size measuring 9.4 cm x 7.5 cm x 7.8 cm. The patient underwent elective caesarian on 08/10/2018 without complications, giving birth to a healthy baby. She is awaiting an endocrine surgeon review for planned adrenalectomy. Conclusion There is only a limited number of reported cases on large adrenal incidentalomas in pregnancy. In fact, we were unable to find any reported evidence of large cystic pheochromocytoma in pregnancy. There is no consensus and guidelines for treating pheochromocytoma during pregnancy, and a multidisciplinary approach should determine management.