# Case Report: Gefitinib in EGFR 19del recurrent aggressive fibromatosis

## TL;DR

A patient with a specific EGFR mutation showed a good response to gefitinib for aggressive fibromatosis after other treatments failed.

## Contribution

This is the first reported case of EGFR 19del mutation in aggressive fibromatosis responding to gefitinib.

## Key findings

- The patient showed a sustained partial response to gefitinib after multiple treatment failures.
- The main side effect was a grade 2 rash, indicating manageable toxicity.

## Abstract

We present the first case of a male patient with an epidermal growth factor receptor (EGFR) 19del mutation who was diagnosed with intra-abdominal aggressive fibromatosis and familial adenomatous polyposis. We assessed the clinical response of the patient to first-generation EGFR-tyrosine kinase inhibitors (EGFR-TKIs). A remarkable sustained partial response was achieved with the application of gefitinib after progression on multiple lines of therapy. The main adverse event of gefitinib treatment in this patient was a grade 2 rash. (Funded by the National Natural Science Foundation of China [Grant No. 82003061] and the Shanghai Sailing Program [20YF1408800] to Yanjing Guo, the Natural Science Foundation of Shanghai [Grant No. 24ZR1412800] to Xin Liu).