A 55-year-old male presented with easy bruising and recurrent nose bleeds.
He had mild anemia with Hb of 7.2 mM, and extensive laboratory work-up showed the presence of an IgM-kappa M-protein of 41 g/l (normal levels of the free light chains), as well as a coagulation tests compatible with acquired von Willebrand’s disease (low VWF antigen, even lower VWF activity, low FVIII, decrease in HMW VWF multimers, and presence of an inhibitory antibody in neutralization assays). There were no signs of hyperviscosity.
Whole body CT showed no abnormalities. Bone marrow examination revealed 25% clonal plasma cells. Cytogenetic evaluation showed hyperdiploidy in the clonal plasma cells, and molecular tests showed no MYD88 mutation. There were no other laboratory abnormalities.