Pleomorphic B cell neoplasm with monoclonal IgA secretion: a case report.

A case of non-myelomatous malignant disease with IgA paraproteinemia is described. A pleomorphic lymphoid/plasmacytoid infiltrate was found in the bone marrow. While the cells studied had some ultrastructural characteristics closer to myelomatosis than Waldenström's macroglobulinemia, immunofluorescence showed IgA in both the cytoplasm and at the cell surface, as seen with IgM in macroglobulinemia but not with IgA in typical IgA myelomatosis. This case illustrates that IgA paraproteinemia may be produced in association with pleomorphic B cell proliferative diseases as well as myelomatosis. There is probably a spectrum of disease states as with IgM paraproteinemia.