"Waldenström's macroglobulinemia" terminating in immunoblastic sarcoma. A case report.

An autopsy case of 69-year-old man with Waldenström's macroglobulinemia terminating in immunoblastic sarcoma is reported. In the course of this case, the appearance of plasmocytoid lymphocytes was initially observed in peripheral blood smears and bone marrow punctures, but lymph node biopsy and bone marrow aspirations performed in the terminal stage, as well as autopsy, revealed a diffuse monotonous proliferation of immunoblasts in the lymphoreticular tissues. With the immunofluorescence method and PAP method of Taylor,11 IgM kappa type of immunoglobulin was demonstrated in the cytoplasm of the proliferating cells, and the electron microscopic enzyme-labeled antibody technique identified localization of the immunoglobulin in the nuclear envelope and rough endoplasmic reticula of the immunoblasts. The results indicate that the initial appearance of plasmocytoid lymphocytes in this case and its terminal transformation into immunoblastic sarcoma are rare phenomena occurring in a single clone proliferation disorder of B-cell synthesizing IGM kappa immunoglobulins.