Histologic examination of a biopsy of one of the masses revealed a diffuse atypical cellular infiltrate with undifferentiated morphology in the submucosa that was positive for CD3, CD4, weak and variable CD79a, CD138, BCL2, CMYC, MUM1, vimentin, and monoclonal cytoplasmic lambda. A diagnosis of recurrent plasma cell myeloma was made. The gene discussed is CD4; the disease is plasma cell myeloma.