Endocrine Abstracts

Background: Pancreatic neuroendocrine tumours (pNETs) are commonly reported in patients with MEN1. The estimated incidence is reported as 40–80% of adults with MEN1 and pNETs are frequently multifocal. Guidelines recommend that CT, MRI and endoscopic ultrasound (EUS) can be used for detection and surveillance of pNETs in MEN1. MRI has been the most commonly used modality, but EUS may be more sensitive in detecting pNETs.

Objective: To compare the sensitivity of CT/MRI and EUS in detecting pNETS in adults with MEN1.

Methods: Extensive review of electronic and paper records was undertaken from 2005–2015. We identified forty three MEN-1 patients, of whom 25 were shown to have pNETs. Of these patients, five did not have EUS for comparison and hence only 20 patients were included in the analysis.

Results: Twenty patients were included (8 M, 12 F, mean age 41.3 years (range 21–56)). All had a confirmed pathogenic mutation in the MEN1 gene. Gut peptides were measured in all patients. Pancreatic imaging using CT and/or MRI was compared with EUS findings. Cross-sectional imaging using MRI/ CT detected abnormality in 14 out of 20 (70%) compared to EUS which found at least one lesion in all 20 patients (100%). Those with negative MRI/CT, had EUS lesions ranging from 3.5–13 mm. Five of these six imaging negative patients were symptomatic, three patients of which included gastrin excess features, two patients with non functional lesion were symptomatic. Seven patients had normal gut peptides; gastrin was elevated in 8 patients, 4 patients had elevation of other gut peptides, while 1 patient had insulinoma.

Conclusion: EUS invariably detected at least one pNET in these adults with MEN1, compared with approximately 70% detection using MRI/ CT. Current guidance exists regarding treatment decisions when pancreatic lesions are >2 cm or associated with hormone hypersecretion. In this series, EUS commonly detected small pNETs in MRI negative symptomatic individuals but the optimal management of these tumours is less established. We conclude that routine use of EUS in pancreatic surveillance for MEN1 patients identifies lesions less than 2 cm more reliably than MRI and should be an integral part of MEN1 surveillance.