A Rare Case of Recurrent Dasatinib-Induced Chylothorax Years After Initial Treatment

Background: Chronic myeloid leukemia (CML) is characterized by the Philadelphia chromosome containing the BCR-ABL protein with deregulated tyrosine kinase activity. Tyrosine kinase inhibitors (TKIs) were developed to target this oncogene. Dasatinib, a TKI, has rarely been associated with spontaneous chylothorax. The majority occur within 1 year of dasatinib initiation and resolve after drug cessation. In contrast, we present a patient with CML on dasatinib therapy for 8 years who developed recurrent unilateral chylothorax even after cessation of dasatinib. Case: A 57-year-old male with a history of CML on dasatinib therapy presented to the hospital for nausea and vomiting. A computed tomographic scan revealed a large right-sided pleural effusion with thoracentesis yielding 1.5 liters of chylous fluid. The patient’s hospital course was complicated by intracranial hemorrhage and subsequent admission to the intensive care unit. Dasatinib was stopped during this time. The patient experienced multiple recurrences of this effusion with significant output via thoracentesis and chest tube despite dietary changes. Lymphangiography was performed but revealed no evidence of thoracic duct leakage. Conclusions: Chylothorax from dasatinib is rare, usually occurs within 1 to 2 years of treatment onset, and resolves with discontinuation. However as supported by this case and others, it may occur as late as 8 years from treatment onset and chylothorax may continually re-accumulate or persist up to 1 year from dasatinib cessation. It is imperative to rule out underlying thoracic duct disruption prior to attributing etiology to dasatinib as a misdiagnosis may result in treatment delays.