SUN-393 Clinical differences among incidental, symptomatic, and genetic screened-pheochromocytomas

Abstract L. Sciotto: None. S. Andrade Lopes: None. C. De Vito: None. F.R. Jornayvaz: None. K. Gariani: None. M.S. Demarchi: None. S. Leboulleux: None. F. Triponez: None. M. Mavromati: None. Pheochromocytomas are rare tumors arising from the adrenal medulla. Their diagnosis can be suspected in case of symptoms related to catecholamine secretion or to the tumor mass. Other reasons leading to diagnosis include screening, in case of a known germline pheochromocytoma, or incidental findings. The objective of our study was to describe clinical characteristics of pheochromocytomas according to the circumstances of diagnosis in a cohort of patients operated between November 2007 and October 2022 in a tertiary academic center. Fifty-four patients (28 female; median age: 47 years, SD: 16.3) with 58 pheochromocytomas, with a median diameter of 35 mm (SD: 23.5), were included. High blood pressure and elevated catecholamines were present in 32 (59%) and 52 (96%) patients, respectively. Germline mutations were present in 13 patients (24%) with 6 mutations already known and 7 newly discovered (RET mutation in 7 cases, VHL mutation in 4 cases, SDHB mutation in 1 case and MLH1 mutation (Lynch syndrome) in 1 case). Reasons leading to diagnosis were symptoms related to catecholamine secretion or tumor size in 22 patients (41%), periodic screening because of a known germline mutation in 6 patients (11%) and incidental in 26 patients (48%). Increased metanephrines were found in 52 patients (96%); metanephrines were normal in one patient with incidental pheochromocytoma and were not measured in one patient with incidental pheochromocytoma diagnosed only on histology. Compared to symptomatic pheochromocytomas, patients with incidental pheochromocytomas had similar median age (47 for symptomatic versus 49 years for incidental findings). Those with germline mutations leading to the diagnosis were younger (median age 31 years). High blood pressure was less frequent in patients with incidental pheochromocytoma (42%), compared to screened pheochromocytomas (50%) and symptomatic pheochromocytomas (82%). Incidental pheochromocytomas were smaller (median diameter (30 mm, SD: 13.2) compared to symptomatic (40 mm, SD:28.5). Twenty nine of the 48 patients without known germline mutation prior to surgery underwent genetic testing. A mutation was found in 7 of them (24%): 2 with symptomatic pheochromocytomas and 5 with incidental ones. Median age at diagnosis of these patients was 46 years (SD: 15.3) and median diameter of the pheochromocytoma was 34 mm (SD:18.6); 5 of these patients had high blood pressure. In conclusion, iIncidental finding is the most frequent mode of discovery of pheochromocytomas, accounting for 48% of cases in our cohort. Incidental pheochromocytomas are smaller and less frequently associated to high blood pressure. Patients with known germline mutations associated to pheochromocytomas that have periodic screening, are diagnosed at a younger age. Sunday, June 2, 2024