Functional Imaging Experience in a Germline Fumarate Hydratase Mutation–Positive Patient With Pheochromocytoma and Paraganglioma

Abstract

ABSTRACT: Objective: To report the functional imaging experience with a 29-year-old woman carrying a mutation in the fumarate hydratase (FH)-encoding gene and a history of a pheochromocytoma (PHEO) and retroperitoneal paraganglioma (PGL).Methods: The patient was found to have a splice-site mutation in the FH gene at intron 2, c.268-2A>G. To confirm this, immunohistochemical staining was performed on tumor tissue slides from the patient's previous surgeries. The patient underwent biochemical testing for PHEO/PGL, which included chromogranin A and plasma methoxytyramine. The patient's tumors were also imaged using several imaging modalities, including computed tomography (CT), magnetic resonance imaging, ultrasound, and positron emission tomography (PET)/CT studies using [18F]-fluorodeoxyglucose ([18F]-FDG), [18F]-fluorodopamine ([18F]-FDA), [18F]-fluorodihydroxyphenylalanine ([18F]-FDOPA), and [68Ga]-tetraazacyclododecanetetraacetic acid–[Tyr3]-octreotate ([68Ga]-DOTATATE) as tracers.Results: The patient received a comprehensive evaluation based on her symptoms and medical history. She was found to have 3 noradrenergic-secreting tumors that showed uptake on [18F]-FDG-(2/3), [68Ga]-DOTATATE-(2/3), [18F]-FDOPA-(3/3), and [18F]-FDA-(3/3) PET/CT. The patient was recommended to have the tumor sites removed (renal hilum, aortocaval, and periaortic regions) with lympadenectomies to address possible metastases. Pathology confirmed paraganglioma. Immunohistochemical staining from previous surgical slides showed negative staining for FH, consistent with a mutation in the gene.Conclusion: We share, for the first time, functional images for an FH mutation–positive PHEO/PGL patient using various PET radiopharmaceuticals. [18F]-FDA- and [18F]-FDOPA PET/CT served as the best imaging modalities. This case provides the appropriate selection of imaging studies and further evidence for the importance of screening for FH mutations in patients with noradrenergic PHEOs/PGLs.Abbreviations: CT = computed tomography [18F]-FDA = [18F]-fluorodopamine [18F]-FDG = [18F]-fluorodeoxyglucose [18F]-FDOPA = [18F]-fluorodihydroxyphenylalanine FH = fumarate hydratase [68Ga]-DOTATATE = [68Ga]-tetraazacyclododecanetetraacetic acid–[Tyr3]-octreotate MTY = methoxytyramine NIH = National Institutes of Health PET = positron emission tomography PGL = paraganglioma PHEO = pheochromocytoma SDHB = succinate dehydrogenase complex, subunit B URL = upper reference limit