A case of anaplastic large cell (Ki-1) lymphoma of B-cell phenotype, occurring in Waldenström's macroglobulinemia.

A case of anaplastic large cell (Ki-1) lymphoma of B-cell lineage occurred in a 59-year-old male with Waldenström's macroglobulinemia. Immunostaining of the lymphoma cells showed sporadic positivity for IgM and occasional positivity for kappa chain. This immunoglobulin specificity is the same as that of plasmacytoid lymphocytes in the bone marrow; therefore anaplastic transformation of Waldenström's macroglobulinemia was strongly suggested. This seems to be the first reported case of anaplastic large cell lymphoma, confirmed by CD30 expression, arising in Waldenström's macroglobulinemia.