[Tc-99m]-HYNIC-octreotide imaging aiding in the diagnosis of von Hippel-Lindau syndrome by detecting pancreatic neuroendocrine tumour, adrenal pheochromocytoma and cerebellar hemangioblastoma

1327 Objectives: Von Hippel-Lindau (VHL) syndrome is a rare neoplastic disorder characterized by retinal and central nervous system (CNS) hemangioblastomas, clear cell renal cell carcinoma (RCC), pheochromocytoma, pancreatic islet tumors and endolymphatic sac tumors. [Tc-99m]-HYNIC-octreotide ([Tc-99m]-TOC) binds to the cell membrane SSTR receptors (subtype 2, 3 and 5). [Tc-99m]-TOC imaging has proven to be very useful for imaging of neuroendocrine tumors (NET). This research was to evaluate [Tc-99m]-TOC imaging in detection and localization of tumors with VHL syndrome. Methods 19 cases (10 males, 9 females; age range: 11 to 60 years) with clinically suspected VHL syndrome were enrolled in this study. All patients were VHL syndrome. The diagnoses were confirmed by pathohistology, gene diagnosis, other examinations or clinical follow-up studies. Regional, whole body and SPECT/CT (in some positive cases) imagings were acquired at 1 and 4 hours after an intravenous injection of 350-400 MBq [Tc-99m]-TOC. All patients gave written informed consent. Twelve cases underwent 131I-MIBG imaging. Results Positive findings were obtained in 16 of 19 cases with VHL syndrome in [Tc-99m]-TOC imaging. [Tc-99m]-TOC imaging demonstrated both pheochromocytoma and pancreatic neuroendocrine tumor(PNET) in 6 cases, both CNS hemangioblastomas and PNET in 1 case, both CNS hemangioblastomas and pheochromocytoma in 1 case, single pheochromocytoma in 6 case, single PNET in 1 case, and single RCC in 1 case. The per-patient detection rate of [Tc-99m]-TOC imaging for detecting tumors with VHL syndrome were 84.2%. Based on the lesion, 34 out of 58 lesions were identified by [Tc-99m]-TOC imaging, including 22 pheochromocytomas, 9 PNETs, 2 cerebellar hemangioma and 1 RCC. The other 24 lesions were confirmed by 131I-MIBG imaging, CT, MRI or fundus fluorescence angiography ( FFA), including 8 pheochromocytomas, 6 RCC, 5 retinal angioma, 4 cerebellar hemangioma and 1 PNET. Two cerebellar hemangioma were firstly localized by [Tc-99m]-TOC imaging, while previous conventional imaging techniques failed to detect them. The per-lesion detection rate of [Tc-99m]-TOC imaging for detecting tumors with VHL syndrome were 58.6%. Conclusion [Tc-99m]-TOC imaging should be used as an initial imaging approach in detection and follow-up of VHL manifestations, screening of asymptomatic gene carriers, and in diagnosis of pheochromocytoma, PNET, CNS hemangioblastomas and RCC.