Clinical utility of functional imaging with ¹⁸F-FDOPA in Von Hippel-Lindau syndrome

Context: Von Hippel-Lindau (VHL) syndrome is an inherited cancer syndrome in which patients are at risk of developing multiple tumors in different organs. 6-L- ¹⁸F-fluorodihydroxyphenylalanine ( ¹⁸F-FDOPA) positron emission tomography (PET) is a relatively new metabolic imaging tracer proposed for the use of localizing sites of neuroendocrine tumors. There are limited data on the clinical utility of using ¹⁸F-FDOPA PET for identifying neuroendocrine tumors in a high-risk population such as VHL. Objective: The aim of this prospective study was to evaluate the clinical utility of ¹⁸F-FDOPA PET in patients with VHL-related tumors. Design: Radiological findings were prospectively collected from four imaging modalities: computed tomography, magnetic resonance imaging (MRI), ¹⁸F- fluorodeoxyglucose PET, and ¹⁸F-FDOPA PET. ¹⁸F-FDOPA PET findings were compared with those from other imaging modalities, as well as with clinical and laboratory data, and pathology findings if patients underwent an operation. Results: In 52 patients with VHL, 390 lesions were identified by computed tomography (n = 139), MRI (n = 117), ¹⁸F-fluorodeoxyglucose PET (n = 94), and ¹⁸F-FDOPA PET (n = 40). ¹⁸F-FDOPA PET identified 20 pancreatic and 20 extrapancreatic tumors, including lesions in the adrenal gland (n = 11), kidney (n = 3), liver (n = 4), lung (n = 1), and cervical paraganglioma (n = 1). These tumor sites were not seen by conventional imaging studies in 9.6% of patients and 4.4% of lesions. Seven of eight patients who had an ¹⁸F-FDOPA PET-positive lesion underwent resection, and pathology showed a neuroendocrine tumor. Four of 10 patients with positive adrenal uptake had elevated catecholamine levels, and six of 10 patients had a discrete mass on axial imaging. Conclusions: ¹⁸F-FDOPA PET is a useful complementary imaging study to detect neuroendocrine tumors in patients with VHL undergoing surveillance, especially in those suspected to have adrenal pheochromocytoma or unusual ectopic locations.