Case Report: Dasatinib-associated chylothorax and occult Bartonella henselae infection in pediatric leukemia: a case report and systematic review.

Dasatinib is a second-generation tyrosine kinase inhibitor (TKI) used in Philadelphia chromosome-positive (Ph+) acute lymphoblastic leukemia (ALL), and chylothorax is one of its rare but serious lymphatic complications. We encountered a 14-year-old boy with Ph + acute lymphoblastic leukemia (ALL) who developed bilateral chylothorax while on dasatinib, with concurrent B. henselae infection (cat-scratch disease) confirmed in the pleural fluid. Prompted by this index case, we performed a systematic review of the literature to explore the potential association between dasatinib-associated chylothorax and Bartonella henselae infection. We searched multiple databases up to March 2026 and identified 24 cases of TKI-associated chylothorax and 11 cases of leukemia-related cat-scratch disease. In our index case, the pleural fluid triglyceride concentration reached 20.40 mmol/L (≈1806 mg/dL)-the highest value reported to date-and mNGS detected B. henselae together with other organisms. After dasatinib was discontinued and the patient received chest drainage, somatostatin, fasting, and anti-infective therapy with doxycycline plus rifampicin, imaging showed near-complete resolution of the effusion, and repeat mNGS confirmed clearance of B. henselae. A formal causality assessment using the Naranjo scale gave a score of 7, indicating a "probable" adverse drug reaction. This case illustrates that lymphatic and infectious complications can coincide in the same patient. Dasatinib-mediated inhibition of Src family kinases may simultaneously impair lymphatic endothelial integrity and suppress T-cell-mediated immune surveillance, thereby facilitating both chylous leakage and opportunistic infection. Clinicians managing paediatric patients receiving long-term dasatinib therapy should remain vigilant for both lymphatic complications and atypical opportunistic infections.