In this report, we provide evidence of an acquired von Willebrand syndrome (AVWS) with a type 2B phenotype rather than the expected type 1 or 2A. The patient was referred prior to surgical removal of a fibrous mass within the maxillary sinus. His first bleeding 7 years earlier following a retinal tear had been complicated by monocular blindness. Several mucocutanous bleedings followed. Hematological investigations revealed von Willebrand factor (VWF):Ag 91 IU/ml, factor VIII 86 IU/ml, VWF:RCo 34 IU/ml and profound thrombocytopenia with platelet clumping. VWF multimer analysis showed a loss of high-molecular-weight multimers and his plasma aggregated normal platelets under low ristocetin concentration, consistent with type 2B von Willebrand disease (VWD). Sequencing of VWF exon 28 and of the platelet GP1BA gene to investigate the possibility of platelet-type VWD failed to reveal mutations. Serum protein electrophoresis showed a monoclonal IgG protein and led to the diagnosis of monoclonal gammopathy of unknown significance (MGUS), raising suspicion of an AVWS. Over 2 years, he experienced severe gingival bleedings and traumatic intracerebral hemorrhage. Following debridement of the sinus mass, the patient required 20 units of packed red blood cells, despite high-dose Humate-P, continuous Amicar and twice-daily platelet transfusions. Bleeding finally ceased following infusion of activated factor VIIa. A history of prior uncomplicated vasectomy and tendon laceration, no family history of bleeding, the inability to identify a causative mutation in either exon 28 VWF or platelet GP1BA and the MGUS led to diagnosis of AVWS with a type 2B phenotype. This case highlights the difficulties in assigning a diagnosis and the management of bleeding in a patient with an atypical presentation of AVWS.