# Concurrent Stage III Unresectable Duodenal Adenocarcinoma and Metastatic Gastrointestinal Stromal Tumor Treated With Combination of Imatinib and mFOLFIRI

## TL;DR

A rare case of two advanced gastrointestinal cancers was successfully treated with a combination of imatinib and chemotherapy.

## Contribution

This case report presents a novel treatment approach for concurrent unresectable duodenal adenocarcinoma and metastatic GIST.

## Key findings

- Combination therapy with imatinib and mFOLFIRI successfully managed both tumors.
- The treatment approach offers a potential strategy for similar rare cancer cases.
- No consistent mutations were found between the two tumors, complicating treatment selection.

## Abstract

Cases of concurrent duodenal adenocarcinoma and gastrointestinal stromal tumors (GISTs) are rare, and only a few have been reported. While some cases of other synchronous primary tumors with GIST have been reported, no shared mutations have been consistently found, creating challenges in selecting chemotherapy in cases of inoperable tumors. Here, we presented a case of a stage IIIA locally advanced/unresectable duodenal adenocarcinoma with concurrent metastatic small bowel GIST successfully being treated with combined imatinib and modified folinic acid, 5-fluorouracil, and irinotecan (mFOLFIRI) regimen.