PB0361 - Acquired von willebrand disease in the diagnosis of IgM multiple myeloma

Background: Multiple myeloma (MM) is the second most common hematological neoplasm; however, IgM MM represents 0.5% of the total cases. IgM MM is a rare entity that can present as an hyperviscosity syndrome (HVS) associated with acquired von Willebrand disease (vWD) and a risk of severe bleeding.

Aims: To present a case report of IgM MM presenting with acquired von Willebrand Disease (vWD) and hyperviscosity.

Methods: A 57-year-old woman was admitted due to spontaneous bruising and persistent gingival bleeding 15 days after dental extraction, accompanied by anemic functional syndrome, blurred vision, and somnolence. Physical examination revealed pale skin, bruises on the upper limbs, and a heart rate of 100 bpm. Coagulation profile showed PT 79.5%, aPTT 46 seconds. In this context, a screening study for vWD was conducted, and it was confirmed.
Further evaluation revealed a peak monoclonal protein (PM) IgM Kappa of 5.9 g/dL. sFLC: Kappa 16.48 and Lambda 4.75, with a ratio of 3.47. Negative 24-hour proteinuria; beta 2 microglobulin of 2.7, LDH of 213 U/l, normal calcium levels. Bone marrow examination showed 60% plasmablasts (image 1).
A literature search was conducted on Pubmed regarding existing cases of IgM MM in the context of vWD. No reported cases were found in the literature.

Results: The literature review revealed that acquired vWD is a rare disorder that can be associated with IgM paraproteinemia, linked to its antibody activity interfering with vWF function. It presents with unusual bleeding. The presence of PM IgM can cause a hyperviscosity syndrome (HVS) due to its high molecular weight and tendency to polymerize. Bortezomib-based regimens are the standard treatment, achieving good responses, as evidenced in this case.

Conclusion(s): IgM MM is a rare entity that can present as an HVS associated with acquired vWD and a risk of severe bleeding. Its prompt recognition has prognostic and therapeutic implications.