# Dasatinib-Induced Polymyositis-Like Syndrome: A Report of a Rare Case

## TL;DR

A rare case of muscle weakness caused by a cancer drug called dasatinib is reported, highlighting the need for monitoring muscle health in patients.

## Contribution

This is the first documented case of dasatinib-induced polymyositis-like syndrome, offering new clinical insight.

## Key findings

- A 24-year-old male developed muscle weakness after dasatinib treatment for CML.
- MRI scans showed diffuse muscular edema, and symptoms improved after stopping dasatinib.
- This case emphasizes the potential for dasatinib to cause myositis-like symptoms.

## Abstract

Myositis is an inflammatory muscle disease characterized by chronic inflammation, progressive muscle weakness, and various systemic effects. Dasatinib, a tyrosine kinase inhibitor (TKI), is commonly used as a first-line treatment for chronic myelogenous leukemia (CML). Although it is generally effective, there have been rare cases where dasatinib can induce muscle damage, leading to muscle weakness. We wanted to highlight a unique case involving a 24-year-old Caucasian male who was treated with dasatinib for CML and subsequently developed proximal weakness in both his upper and lower extremities. Imaging studies, including multiple MRI scans, revealed diffuse muscular edema. Importantly, the patient did not receive steroid treatment; however, his symptoms significantly improved after discontinuing dasatinib. This case is a noteworthy contribution to the understanding of dasatinib-induced polymyositis-like syndrome, as it represents the first documented instance, to the best of our knowledge, based on our literature review. Such cases emphasize the need for close monitoring of muscle health in patients receiving dasatinib and encourage further investigation into the relationship between this medication and myositis.