Rituximab-Induced Acute Coronary Syndrome.

Rituximab is a chimeric monoclonal antibody that selectively targets CD20+ B lymphocytes, making it an effective therapeutic agent in managing diseases where B cells play a critical role in the pathogenesis. The depletion of B lymphocytes is a crucial therapeutic effect in treating both lymphoproliferative disorders and autoimmune diseases.  We present the case of an elderly male with splenic marginal zone lymphoma who developed acute chest pain during rituximab chemotherapy infusion, raising suspicion for rituximab-induced acute coronary syndrome (ACS). Despite an initial rise in cardiac biomarkers (troponin T), the electrocardiography showed no significant changes. The chest pain resolved promptly after discontinuing the rituximab infusion. Due to a low platelet count, primary percutaneous coronary intervention (PCI) was not performed, and instead, a computed tomography (CT) coronary angiogram was used to confirm the ACS diagnosis. The patient was treated conservatively, and rituximab therapy was temporarily halted. This case emphasizes the importance of considering the potential cardiotoxic effects of rituximab, particularly in patients with pre-existing cardiovascular risk factors.