Immunoblastic lymphadenopathy-like T cell lymphoma evolving into a massive plasma cell proliferation with biclonal paraproteinemia.

We present a case of immunoblastic lymphadenopathy-like T cell lymphoma (IBL-T) who subsequently developed a massive proliferation of plasma cells. At diagnosis of IBL-T, the patient had polyclonal hypergammaglobulinemia and subsequently, while on chemotherapy, developed paraproteinemia with biclonal peaks and the IBL-T lesion was replaced with a massive proliferation of CD38-positive plasma cells. The evolution was not likely to be attributed to a new neoplastic proliferation of B cells. It appeared that two B cell clones possibly had a growth advantage among the polyclonal B cells due to a depletion of suppressor T cells or to a disturbance in the immune system.