Multiple M components in two patients with splenic lymphoma with villous lymphocytes

Splenic lymphoma with villous lymphocytes (SLVL) is a rare lymphoproliferative disorder characterized by the presence of typical lymphoid cells with villous projections and monoclonal immunoglobulin (M-Ig) in about 30% of patients. The simultaneous presence of more than one M-Ig in SLVL has not been reported. We present two patients with SLVL, each with three serum M components associated with the presence of rheumatoid factor (RF) and antiphospholipid antibodies (APLA) together with fatal thromboembolic events. Both patients presented with splenomegaly and typical bone marrow cytology with 30-50% infiltration of lymphoid cells that had the characteristics of villous lymphocytes. Immunohistochemistry of bone marrow histology showed CD20++, CD43-/+, CD5-, IgM+, lambda+ and kappa-. In serum, two M-IgM lambda components were combined with M-IgG lambda in case 1 and with M-IgA lambda in case 2. In both cases, M-IgM displayed RF as well as lupus anticoagulant activity and free monoclonal lambda (lambda) light chains were present. In addition to M-IgM, in case 1 M-IgG also behaved like an APLA. One patient was splenectomized. Both patients suffered thromboembolic complications and died 3 and 8 months after presentation with signs of massive pulmonary thromboembolism.