Recurrent Chylous Pleural Effusions in a Patient Treated With Dasatinib

Dasatinib is a second-generation BCR-ABL tyrosine kinase inhibitor (TKI) that is approved for the treatment of chronic myeloid leukemia (CML), a myeloproliferative disorder seen commonly in adults over the age of 50. Dasatinib is superior in tolerance and efficacy to first-generation TKIs such as imatinib, given its ability to target mutation products that are resistant to first-generation TKIs. One of the common side effects of dasatinib includes pleural effusion which can be seen in up to 25% of patients on treatment. These effusions are predominantly exudative; however, they tend to resolve upon discontinuation of the drug. While infrequent, chylous effusions have been reported with the use of dasatinib; they tend to resolve following discontinuation of the drug. We present a case of a patient who was treated with dasatinib and developed a chylous effusion which was refractory to the discontinuation of the medication. Our patient was switched to imatinib and since his first episode, he has had multiple reaccumulation requiring thoracentesis, all of which have revealed chylous pleural fluid as per fluid analysis. We present this case to highlight a rare adverse effect of dasatinib which, via an unknown mechanism, can potentially lead to irreversible damage to the lymphatic duct resulting in recurrent chylous effusions.