LAUSR

Dasatinib is a tyrosine kinase inhibitor for the treatment of BCR-ABL-positive chronic myeloid leukaemia (CML) or Philadelphia chromosome-positive acute lymphoblastic leukaemia (ALL). Although fluid retention is a common adverse event associated with dasatinib, chylothorax is exceptionally rare. The pathological mechanism, clinical manifestation and management of dasatinib-induced chylothorax are completely unclear. A 71-year-old man treated with dasatinib for CML was admitted for progressive dyspnea. Computed tomography (CT) showed a pleural effusion that was more prominent on the right thoracic cavity. Thoracentesis showed thick milky pleural fluid, which was then confirmed as chylothorax by chylum qualitative tests and triglyceride measurements. Radionuclide lymphoscintigraphy yielded an obstruction at the end segment of the thoracic duct, but no leakage points were found. After excluding common causes, drug-induced chylothorax was presumed. Then, dasatinib was withdrawn, and 1 week later, chylothorax resolved. To further elucidate the relationship between the medication and chylothorax, dasatinib was resumed tentatively for 2 days. As expected, pleural effusion recurred soon. Based on these clinical manifestations, the diagnosis of dasatinib-induced chylothorax was identified. The patient was suggested to stop dasatinib and use an alternative drug as recommended by the haematologist. Pleural effusion is the common adverse reaction of dasatinib, but chylothorax is rare. Only six cases of dasatinib-induced chylothorax have been reported, and our patient is the seventh case. Once a patient with dasatinib treatment develops chylothorax, dasatinib should be considered one of the possible causes. If no other definitive aetiological factor is identified, dasatinib discontinuation might be the optimum scheme.