The natural history of pancreatic neuroendocrine neoplasms (PNENs) in patients with Von Hippel-Lindau (VHL) disease is poorly defined. Management of patients with PNENs is challenging because there are no reliable preoperative criteria to detect malignant lesions, and the majority of resected tumors are found to be benign. The aim of this study was to determine whether 18-fluorodeoxyglucose-positron emission tomography (18FDG-PET) uptake predicts growth and detects malignant VHL-associated PNENs.
We performed a prospective study of 197 patients with VHL-associated pancreatic lesions. Clinical and imaging characteristics were analyzed to study the associations between FDG-PET uptake, tumor growth, and the development of metastatic disease.
One hundred nine of 197 patients had solid pancreatic lesions and underwent both CT and 18FDG-PET scanning, which identified 165 and 144 lesions, respectively. Metastatic disease was detected by 18FDG-PET in 3 patients in whom it was not detected by CT scan and suggested non-neoplastic disease in 3 patients. Maximum standardized uptake values (SUV) on 18FDG-PET correlated with tumor size on CT (r = 0.47, p < 0.0001), and an increase in SUVmax was associated with tumor growth (r = 0.36, p = 0.0062). No association was seen between 18FDG-PET uptake and age, VHL genotype, or serum chromogranin A levels.
Scanning with FDG-PET identifies metastatic disease not detected by CT scan and avoids resection of non-PNEN lesions that have no malignant potential in patients with VHL-associated PNENs. It should be considered as a valuable functional imaging modality in the clinical management of patients with VHL-associated PNENs.