# Pancreatic Neuroendocrine Tumor Leading to a Diagnosis of Multiple Endocrine Neoplasia Type 1

## TL;DR

A pancreatic tumor led to the diagnosis of a rare genetic disorder affecting multiple endocrine glands.

## Contribution

This case report highlights the role of endoscopic ultrasound in diagnosing MEN1 through a pancreatic tumor.

## Key findings

- A pancreatic neuroendocrine tumor was diagnosed using endoscopic ultrasound and biopsy.
- The patient was found to have multiple endocrine neoplasia type 1 with concurrent hyperparathyroidism and a pituitary adenoma.
- The tumor was also identified in the duodenum, supporting the MEN1 diagnosis.

## Abstract

Pancreatic neuroendocrine neoplasms are rare but occasionally encountered. They are generally highly vascularized solid tumors, often round in shape with clear boundaries, defined contours, and a homogeneous internal structure. However, they can also present with atypical features, such as cystic degeneration, hemorrhage, calcification, and fibrosis, making diagnosis difficult in some cases. They are also known as comorbidities of multiple endocrine neoplasia type 1 (MEN1). This report describes a case in which endoscopic ultrasound (EUS) led to a diagnosis of MEN1. A 50‐year‐old man was referred to our hospital for examination of a mass in the pancreatic body. An EUS‐guided fine‐needle biopsy was performed, and a histological diagnosis of neuroendocrine tumor (NET) was made. In addition, the NET was also identified in the duodenum. Serum calcium and parathyroid hormone levels were elevated. Examination of the parathyroid and pituitary glands revealed concurrent hyperparathyroidism and a pituitary adenoma, confirming the diagnosis of MEN1, including a NET in the duodenum.