Multifocal pancreatic PPoma in the setting of MEN1: Case report and review of literature.

Arman Mosenia,Casey Ward,Amir Qorbani,Carlos Corvera,Alisa Yee

doi:10.1016/j.ijscr.2021.106008

Abstract

Introduction and importanceFunctioning pancreatic neuroendocrine tumors (pNETs) that express pancreatic polypeptide—PPomas—do not yet have a pathognomonic clinical syndrome associated with them due to their overall rarity and diverse symptoms. Moreover, in patients with MEN1, the often multifocal nature of pNETs presents a unique clinical issue.Case presentationWe report a case of a 22-year-old man with a known MEN1 gene mutation who was suffering from severe diarrhea (7–8 bowel movements per day) and was found to have only elevated PP levels on biochemical work-up. Ga68-DOTATATE PET/CT showed multifocal tumors in the body and tail of the pancreas that were not evident on contrast-enhanced CT. The patient underwent a successful laparoscopic radical antegrade modular pancreatosplenectomy (RAMP) and recovered well post-operatively with complete resolution of his diarrhea. Immunohistochemistry showed multiple pure PPomas.Clinical discussionThis case highlights the unique propensity for multifocal disease in patients with MEN1 mutations and the utility of functional imaging by somatostatin analogs, i.e., Ga68-DOTATATE PET/CT, in order to perform oncologic laparoscopic pancreatic resections.ConclusionPPomas in the setting of MEN1 mutations are a unique clinical entity due to their diverse associated clinical syndromes and propensity for multifocal disease.

Highlights

Introduction and importanceFunctioning pancreatic neuroendocrine tumors that express pancreatic polypeptide—pancreatic polypeptide-producing tumor (PPoma)—do not yet have a pathognomonic clinical syndrome associated with them due to their overall rarity and diverse symptoms
Pancreatic Neuroendocrine tumors (NETs), which account for 7% of all NETs, and stem from various cells within the islets of Langerhans [1], are relatively rare but their incidence has been increasing over the past decade, from 1–2 to 5–7 per 100,000 per year across North America [2,3]. pancreatic neuro endocrine tumors (pNET) range from low-grade indolent tumors to high-grade malignant tumors with high metastatic potential [4] and are further categorized into functioning or non-functioning based on their clinical manifestations
PPomas arise from F cells, which are diffusely located within the uncinate and head of the pancreas and produce >90% of the body's pancreatic polypeptide (PP) [8]

Summary

Introduction

Neuroendocrine tumors (NETs) are diverse neoplasms that most often originate in the gastrointestinal tract, lungs, and pancreas. Functioning pNETs are named based on their predominant hormone-related syn drome, such as insulinomas, gastrinomas, vasoactive intestinal polypeptide-secreting tumors (VIPomas), glucagonomas, somatostati nomas, and other rare functional tumors including pancreatic polypeptide-producing tumor (PPoma). MEN1 is inherited in an auto somal dominant fashion and may confer a varying combination of more than 20 endocrine and nonendocrine tumors, rarely known to include multifocal pNETs. The most common pNET in MEN1 is gastrinoma (~40%), with PPoma found in

Case presentation

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