# Recurrent Gastrointestinal Stromal Tumor With Chondroid Differentiation After Imatinib Therapy: An Unusual Case and Literature Review

## TL;DR

This paper reports a rare case of a gastrointestinal stromal tumor with chondroid features after imatinib treatment and compares it with similar cases in the literature.

## Contribution

The novelty is the first documented case of recurrent GIST with chondroid differentiation at the primary site after imatinib therapy.

## Key findings

- A 58-year-old patient had recurrent GIST with chondroid differentiation after two rounds of imatinib therapy.
- The case highlights the possibility of chondroid differentiation in GIST post-imatinib therapy, which can mimic other malignancies like chondrosarcoma.
- A mini-literature review compares this case with others to explore histomorphological and demographic patterns.

## Abstract

Gastrointestinal stromal tumor (GIST) is the most common mesenchymal tumor in the gastrointestinal tract and is most commonly seen in the stomach. The standard treatment for patients with advanced GISTs include both surgical resection and imatinib therapy. There have been cases that document the alterations of patients' GIST histomorphology both with primary GIST prior to imatinib therapy and with recurrent GIST after imatinib therapy. However, there has been no documented case of a patient who has recurrent GIST with chondroid differentiation at the primary site after imatinib therapy.

In this article, we report an incidental finding of a 58-year-old patient who had two treatments of imatinib therapy prior to surgical resection of her recurrent GIST in her stomach. We also explore through a mini-literature review the various cases of GIST with chondroid differentiation that have been reported to compare the histomorphology, immunophenotype, and patient demographic of these cases. This article is significant for reporting a rare finding of GIST after imatinib therapy and highlights the various presentations that GIST could acquire after imatinib therapy that exclude another malignant process, such as chondrosarcoma.