SAT305 Clinical Characteristics And Outcomes Of Patient With Metastatic Pheochromocytoma/Paraganglioma (PPGL) And Extreme Elevated Biochemistry

Disclosure: T. Prodanov: None. A. Jha: None. S. Talvacchio: None. M. Nazari, MD: None. K. Pacak, MD, PhD: None. Background: Pheochromocytomas and paragangliomas (PPGLs) are rare neuroendocrinetumors arising from chromaffin cells in adrenal or extra-adrenal locations,respectively. PPGLs are characterized by an excessive production ofcatecholamines and/or metanephrines. Most of the symptoms of PPGLs, likehypertension, headaches, palpitation, sweating, and anxiety are an effect ofoverproduction of catecholamines and/or metanephrines. Metastatic PPGLs mayoccur in as many as 35% of patients, with higher metastatic potential observed in succinatedehydrogenase subunit B (SDHB)-related tumors (up to 90%). ClinicalCase: A retrospective analysis of 422patients with metastatic PPGL diagnosed and treated from 2000 to 2023 at theNational Institutes of Health, in Bethesda, Maryland, was conducted. We found42 patients with extremely elevated free plasma normetanephrine levels.Extremely elevated level was defined if the value was 100 times or more higherthan the upper reference limit. Free plasma normetanephrine and metanephrinewere measured. Therelated descriptive analyses of this cohort are as follows: 18 (42.8%) werefemales, 24 (57.2%) were males. The average age of patients at the time of theprimary tumor diagnosis was 39.3 ± 44 years. At theirinitial presentation, there were 29 (69.1%) patients with solitary tumors; and13 (30.9%) with metastatic tumors. In 20 (47.6%) patients, primary tumor waslocated in the adrenal gland, 19 (45.3%) had extra-adrenal PGL and head andneck PGL was seen in 3 (7.1%) patients. The average time interval to metastaticdisease was 5.7 ± 20 years. Thirteen(30.9%) patients had metastatic disease at the initial presentation. Theelevated plasma normetanephrine values ranged from 11407 to 69697 pg/mL (normalrange 18-112 pg/mL). The highest level was 622 times above upper referencelimit. None of the patients were found with elevated metanephrine 100 timesthat of upper reference limit.Genetictesting showed pathogenic variants in SDHB in 22 (52.4%), SDHA in2 (4.7%), NF1 in 2 (4.7%), VHL in 1 (2.3%), IDH1 in 1 (2.3%),and apparently sporadic disease in 12 (28.6%) patients, respectively. Overallsurvival, defined as time from diagnosis until last follow up/death was 11.47 ± 22.5 years.Twentypatients received CVD therapy, 13 patients received (131)I-MIBGtherapy, 4 patients received (177)Lu-DOTATATE therapy, 9 receivedlocalized radiation therapy. Thirty-nine out of 42 (92.8%) patients died due tometastatic PPGL most likely related to cardiovascular complications. Conclusion:Patients presented with extremely elevatednormetanephrine levels were found to have poorer prognosis as 92.8% (39/42) ofpatients died due to complications associated with their disease. Patients whopresent with extremely elevated plasma metanephrines should be carefullymonitored and managed. Presentation: Saturday, June 17, 2023