7768 Hereditary Phaeochromocytoma/Paraganglioma And Aortopathy In A Patient With Known Macroprolactinoma: A Series Of Incidental Findings

Abstract Disclosure: J.R. Kelly: None. S. Soule: None. P.J. Hunt: None. Background: The three P association (3PAs) describes the combination of pituitary adenoma and phaeochromocytoma/paraganglioma. Recent case series describe a range of underlying genetic causes, including SDH mutations. We describe a patient with a macroprolactinoma and their subsequent incidental diagnoses of phaeochromocytoma and paraganglioma, with a pathogenic SDHA mutation. Clinical Case: A 58-year-old man had previously received a combination of medical therapy with cabergoline and transsphenoidal debulking surgery for a histologically confirmed macroprolactinoma. Due to a small risk of valvulopathy associated with cumulative doses of cabergoline, screening echocardiogram was requested after seven years of treatment. This showed a calcified bicuspid aortic valve and severe dilatation of the ascending aorta at 58mm. Prior to surgical repair, CT aorta was requested, which showed an incidental left adrenal lesion. Formal adrenal imaging and functional assessment confirmed a 50mm phaeochromocytoma, with a right para-aortic paraganglioma subsequently revealed on Ga-68 DOTATATE-PET scan. He described symptoms of catecholamine excess, with episodic palpitations, chest pain, and increasing anxiety over the previous year, on a background of hypertension. Hereditary phaeochromocytoma/paraganglioma gene panel revealed a pathogenic mutation in SDHA (c.1663+1G>T) – a splicing variant, likely resulting in nonsense decay. Screening was recommended for his three children. He initiated alpha blockade with doxazosin, then beta blockade with metoprolol, prior to open adrenalectomy and excision of paraganglioma. Histology confirmed a left phaeochromocytoma (Ki67 0.1%, PASS score 8, no vascular or capsular invasion) and a paraganglioma. Post-operative plasma normetanephrine normalised (406 pmol/L, pre-operative 6776 pmol/L, normal <1200 pmol/L) and the patient described resolution of symptoms. He subsequently underwent tissue aortic valve replacement and Bentall’s procedure. Histology showed severe atherosclerosis with diffuse medial degeneration of the aorta. Repeat Ga-68 DOTATATE-PET seven months later showed no evidence of residual or recurrent disease. Ongoing management includes cabergoline, annual plasma metanephrine measurement, and intermittent MRI of pituitary and base of skull to coccyx. Conclusion: Macroprolactinomas are relatively common, with only a small proportion associated with underlying genetic abnormalities. This case describes a patient with 3PAs, initially presenting with a macroprolactinoma, with incidental detection of phaeochromocytoma and paraganglioma and subsequent identification of a pathogenic SDHA mutation. In the context of a calcified bicuspid aortic valve and severe aortic dilatation, pre-operative alpha blockade allowed successful surgical management of both potentially life-threatening conditions. Presentation: 6/3/2024