# Bilateral Chylothorax After 13 Years of Dasatinib Therapy in a Patient With Chronic Myeloid Leukaemia: A Case Report

## TL;DR

A man with chronic myeloid leukaemia developed a rare condition called chylothorax after 13 years of taking dasatinib, and stopping the drug improved his condition.

## Contribution

This case report highlights chylothorax as a rare but important side effect of long-term dasatinib therapy.

## Key findings

- Dasatinib-induced chylothorax is an extremely rare but possible complication in long-term CML treatment.
- Discontinuation of dasatinib led to clinical improvement in this patient.
- Chylothorax should be considered as a potential cause of pleural effusion in patients on long-term dasatinib.

## Abstract

A 52‐year‐old man with chronic myeloid leukaemia (CML) who had been receiving dasatinib 100 mg/day for 13 years presented with progressive dyspnea. Chest radiography revealed bilateral pleural effusions, and further evaluation confirmed the diagnosis of chylothorax. Dasatinib‐induced chylothorax was suspected, and discontinuation of the drug led to clinical improvement. Dasatinib is a tyrosine kinase inhibitor (TKI) used for the treatment of CML and Philadelphia chromosome–positive acute lymphoblastic leukaemia (Ph + ALL). Although pleural effusion is a relatively common adverse effect, chylothorax is an extremely rare complication. This case highlights the importance of considering chylothorax as a potential cause of pleural effusion in patients undergoing long‐term dasatinib therapy. In addition, based on the presumed pathophysiological mechanism, drug discontinuation appears to be the most crucial therapeutic approach for dasatinib‐induced chylothorax.

A 52‐year‐old man with chronic myeloid leukaemia developed bilateral chylothorax after 13 years of dasatinib therapy, presenting with progressive dyspnea. Although pleural effusion is a relatively common adverse effect of dasatinib, chylothorax is an extremely rare complication. Based on the presumed pathophysiological mechanism, this case highlights that drug discontinuation is the most crucial therapeutic approach and that chylothorax should be considered in patients with pleural effusion during long‐term dasatinib treatment.