[The pathology and genetic background of lymphoplasmacytic lymphoma/Waldenström macroglobulinaemia]

Lymphoplasmacytic lymphoma is a rare low-grade B-cell lymphoma, which is composed of a mixture of small lymphocytes, plasmacytoid cells and plasma cells that typically infiltrate the bone marrow, but lymph nodes and rarely other organs can be involved as well. Waldenström macroglobulinaemia is a lymphoplasmacytic lymphoma with typical bone marrow involvement and is associated with detectable IgM paraproteins. The diagnosis of lymphoplasmacytic lymphoma/Waldenström macroglobulinaemia (LPL/WM) can be challenging, due to similarities to other small B-cell lymphomas with plasmacytic differentiation and/or with IgM paraproteins. The recently discovered MYD88 mutation may help in the diagnosis, as it is present in over 90% of LPL/WMs. This short review covers the pathology of LPL/WM and offers some insight into the new molecular findings that may help in the diagnostic procedure and in the new therapeutic choices.