Successful Treatment of Acquired von Willebrand Syndrome in a Rare Case of Nodal Marginal Zone Lymphoma With Rituximab Therapy: A Case Report.

Nodal marginal zone lymphoma (NMZL) is an uncommon, mature B-cell lymphoma, rarely associated with acquired von Willebrand syndrome (AVWS), a bleeding disorder caused by von Willebrand factor (VWF) defects secondary to lymphoproliferative disorders (LPDs). We report a 68-year-old woman with longstanding Sjögren's syndrome, presenting with persistent oral bleeding, anemia, prolonged activated partial thromboplastin time (APTT, 50.5 seconds), and IgA-λ monoclonal gammopathy. Further investigation revealed severely decreased VWF ristocetin cofactor activity (VWF:RCo, 16%). Imaging revealed systemic lymphadenopathy, and a lymph node biopsy confirmed NMZL. The patient was treated with four weekly doses of rituximab, resulting in cessation of bleeding, improvement of coagulation parameters, resolution of anemia, and significant lymphadenopathy regression - consistent with complete response by computed tomography (CT) per Lugano 2014. This case highlights the diagnostic challenges of AVWS associated with NMZL and demonstrates rituximab's efficacy in treating both lymphoma and AVWS.