Macroglobulinemia and Chronic B-Cell Type Lymphocytic Leukemia in Japan — Study of Autopsy Cases —

: Autopsy cases of Waldenstrom's macroglobulinemia (WM) and chronic lymphocytic leukemia of B-cell type (B-CLL) were examined to determine the geographical distribution and histological characteristics of these diseases in Japan. Both diseases occurred primarily at 50 to 60 years of age with a predominance of males and were distributed throughout Japan with a population slightly lower than that of T-CLL in southwestern Japan. Histologically WM (31 cases) consisted mainly of small cell type malignant lymphoma with plasmacytic differentiation (27 cases) according to the Japanese Classification (LSG) and cytoplasmic immunoglobulins with a monoclonal pattern of immunoglobulin M (IgM) (lambda 12; kappa seven). The bone marrow involvement (27 cases) was follicular, mixed (follicular and diffuse) or diffuse. B-CLL (58 cases) also showed principally a small cell type histology (48 cases) and 16 of the cases showed plasmacytic differentiation as in WM. Cytoplasmic immunoglobulins with a monoclonal pattern were found in 10 (six of IgG, two of IgM, one of IgG and M, and one of IgA). Bone marrow involvement (56 cases) revealed the same histological pattern as WM. According to the growth pattern of the tumor cells in the bone marrow and lymph nodes, both diseases may be categorized as bone marrow-based lymphoma.