Gastrinomas and non-functioning pancreatic endocrine tumors in multiple endocrine neoplasia syndrome type-1 (MEN-1)

Purpose: Illustrate imaging findings of gastrinomas and non-functioning pancreatic endocrine tumors (NF-PNET) in a patient with multiple endocrine neoplasia type-1 (MEN-1) syndrome with a radiologic-pathologic correlation for both along with the results of a 13 yrs observational study. Methods: A 48 yrs old male patient with MEN-1 and a Zollinger-Ellison syndrome was submitted to a duodeno-cephalopancreatectomy (DCP) extended to the pancreatic body to remove several gastrinomas shown by an endoscopic-ultrasonography as well as a large (> 2 cm) hypo-vascular pancreatic nodule shown by a contrast-enhanced multi-detector CT (CE-MDCT). Further conventional (CT/MR) and functional imaging (68Ga-PET-DOTA-TOC) studies were performed over the next 13 years. Results: Up to 14 gastrin-positive NET-G1 (pT2,N1) as well as a single PNET-G2 (pT2,N0) were found at histo-pathology which also showed a NET-G1 in the uncinate process where CE-MDCT documented a 9 mm hyper-vascular nodule. A 7 mm pancreatic nodule with identical contrast-enhancement pattern was also shown at the level of the pancreatic tail which was left to preserve endocrine function. At this level, follow-up studies documented the occurence of a small (< 1 cm) hypo-vascular nodule which was metastatic at presentation and rapidly progressed under somastatin-analogs therapy whereas the hyper-vascular nodule remained stable over 13 years. Both the pancreatic lesion as well as the hepatic metastasis showed pathologic uptake of the radiotracer with a SUVmax of 6.3 and 29.5, respectively, allowing the patient to be scheduled for a Peptide Receptor Radionuclide Therapy performed with 29.6 GBq of 177Lu-Oxotreotide. Conclusions: Contrast-enhancement patterns are correlated with both the histological grade as well as the biological behaviour of PNETS.