# Characteristics, therapy, and outcome of rare functioning pancreatic neuroendocrine neoplasms

## TL;DR

This study examines rare functioning pancreatic tumors, finding that complete tumor removal and absence of liver involvement are linked to better survival.

## Contribution

The paper provides a detailed retrospective analysis of a rare subset of pancreatic tumors with insights into their characteristics and outcomes.

## Key findings

- All 12 patients had their tumors visualized preoperatively, with six having distant metastases at diagnosis.
- Nine patients had tumors in the pancreatic tail, and 11 underwent resection with nine achieving R0 status.
- Five of six surviving patients had no evidence of disease after a median follow-up of 75 months.

## Abstract

Functioning pancreatic neuroendocrine neoplasms other than insulinomas and gastrinomas (rf-pNENs) are exceptionally rare tumours. Thus, their characteristics and long-term prognosis have not been well defined. This article aims to present data and experience from a single institution concerning this topic. Twelve of 216 (5.5%) patients with pNENs operated between 2002 and 2022 in the ENETS Centre of Excellence Marburg had rf-pNENs and their data were retrospectively analysed. We identified three vasoactive intestinal polypeptide producing pNENs, four glucagonomas and five calcitoninomas. The tumour could be visualised by preoperative imaging in all 12 patients, and six patients had distant metastases at the time of diagnosis. The tumour was located in the pancreatic tail in nine patients and the median tumour size was 82 (range 12–220) mm. Eleven patients underwent tumour resections (two robotic, nine conventional), nine of which were R0. After a median follow-up of 75 (range 1–247) months, six patients were alive, five of whom had no evidence of disease. All patients who remained disease-free had an initial R0 resection of the primary tumour and no initial liver involvement. This study sheds light on the distinct characteristics and outcomes of these exceedingly rare tumours, offering insights for improved understanding and management.