Acquired Bernard-Soulier-like syndrome due to a plasma-based inhibitor treated successfully with rituximab

Background: Bernard-Soulier syndrome (BSS) is an autosomal recessive disorder caused by deficient platelet glycoprotein Ib-IX-V expression resulting in abnormal bleeding, thrombocytopenia, giant platelets, and reduced platelet aggregation response to ristocetin that manifests in childhood. Acquired BSS is a rare disorder characterized by Bernard-Soulier (BS)-like platelet dysfunction in a patient without a history consistent with a bleeding disorder. Key Clinical Question: Can acquired BSS respond to immune-directed therapy? Clinical Approach: We describe a case of a 79-year-old man presenting with refractory epistaxis found to have an isolated BS-like platelet function defect due to a plasmabased inhibitor. He was treated with rituximab with immediate cessation of bleeding and normalization of platelet function studies. Conclusion: To our knowledge, this is the first case of acquired BS-like syndrome described in the absence of systemic illness due to a presumed autoantibody, and we report the successful use of rituximab for treatment of this rare disorder.