Characterization of metabolic and imaging profiles in the diagnosis of succinate dehydrogenase- related hereditary pheochromocytomas and paragangliomas.

purposeHereditary pheochromocytomas and paragangliomas can be associated with mutations in the mitochondrial enzyme succinate dehydrogenase. Due to their heterogenous clinical presentation, no clear universal screening guidelines are currently available. We sought to examine the utility of metabolic testing and imaging in diagnosing hereditary pheochromocytomas and paragangliomas. MATERIALS AND

methodsOur retrospective study included patients with confirmed familial succinate dehydrogenase mutations and histologically proven pheochromocytomas/paragangliomas or with suggestive metabolic and imaging features. We extracted information on age, race, sex, tumor size, tumor location, presence of metastatic disease and other succinate dehydrogenase-associated manifestations, urine and plasma metabolic testing, and diagnostic imaging. Patients who lacked any diagnostic information were excluded.

resultsOur cohort consisted of 9 patients with 13 tumor occurrences from 2003 to 2023. The average age at diagnosis was 31.7 years with a 2.9 cm average tumor size. Three patients developed metastatic disease. Five tumors (38.5%) were biochemically silent, with all tumors detected on imaging. Most of the remaining tumors had a noradrenergic profile, with positive norepinephrine and normetanephrine in plasma and urine. I-123 MIBG was the least sensitive (50%) imaging modality, and Ga-68 DOTATATE PET/CT was the most sensitive (100%). 10 (76.9%) tumors were treated with surgical resection; all metabolic results were subsequently negative, except in patients with metastatic disease.

conclusionsOur investigation adds to the current literature on diagnosing hereditary pheochromocytomas and paragangliomas. We highlight the importance of multimodal screening that consists of both imaging and metabolic screening, especially given the prevalence of biochemically silent tumors.