Transient Acquired von Willebrand Disease With a Type 2B Phenotype: Recognizing the Diagnostic Challenges.

Acquired von Willebrand disease (vWD) may arise secondary to autoimmune conditions, hematologic malignancies, or valvular heart dysfunction. It should be included in the differential diagnosis of any acquired bleeding disorder. Most cases resemble Type 1 or Type 2A inherited vWD, typically presenting with variable decreases in von Willebrand antigen and activity. However, clinicians should exercise caution when interpreting von Willebrand panels to rule out acquired vWD, as acute phase reactants - associated with inflammation and malignancy - can artificially elevate and normalize circulating von Willebrand factor (vWF) and factor VIII levels. We present a rare case of acquired vWD with a Type 2B phenotype on platelet aggregation studies, temporally associated with diffuse large B-cell lymphoma (DLBCL). vWF and multimer assays were non-contributory, likely due to elevated acute phase reactants at the time of diagnosis, evidenced by increased factor VIII activity and falsely elevated von Willebrand antigen and activity levels. The patient's bleeding symptoms resolved following lymphoma treatment and remission. Platelet aggregation normalized, factor VIII levels returned to baseline, and von Willebrand activity stabilized. To the best of our knowledge, this case is the first to describe an association between acquired vWD with a Type 2B phenotype and DLBCL, expanding the range of hematologic malignancies linked to this rare presentation. We emphasize diagnostic challenges, particularly the role of acute-phase reactants in obscuring von Willebrand panel interpretations.