Clinical Utility of Functional Imaging with 18F-FDOPA in Von Hippel-Lindau Syndrome

Abstract

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. The aim of this prospective study was to evaluate the clinical utility of ¹⁸F-FDOPA PET in patients with VHL-related tumors. 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. 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. 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.