Gallbladder Paraganglioma Associated with SDHDMutation: a Potential Pitfall on 18F-FDOPA PET Imaging

A 36-year-old male patient initially presented with hypertension, tinnitus, bilateral carotid masses, a right jugular foramen, and a periaortic arch mass with an elevated plasma dopamine level but an otherwise normal biochemical profile. On surveillance MRI 4 years after initial presentation, he was found to have a 2.2-cm T2 hyperintense lesion with arterial enhancement adjacent to the gallbladder, which demonstrated avidity on 68Ga-DOTATATE PET/CT and retrospectively on 18F-FDOPA PET/CT but was non-avid on 18F-FDG PET/CT. Biochemical work-up including plasma catecholamines, metanephrines, and chromogranin A levels were found to be within normal limits. This lesion was surgically resected and was confirmed to be a paraganglioma (PGL) originating from the gallbladder wall on histopathology. Pheochromocytoma (PHEO) and PGL are rare tumors of the autonomic nervous system. Succinate dehydrogenase subunit D (SDHD) pathogenic variants of the succinate dehydrogenase complex are usually involved in parasympathetic, extra-adrenal, multifocal head, and neck PGLs. We report an unusual location of PGL in the gallbladder associated with SDHDmutation which could present as a potential pitfall on 18F-FDOPA PET/CT as its normal excretion occurs through biliary system and gallbladder. This case highlights the superiority of 68Ga-DOTATATE in comparison to 18F-FDOPA and 18F-FDG in the detection of SDHD-related parasympathetic PGL. ClinicalTrials.gov Identifier: NCT00004847.