CD138-positive and Kaposi's sarcoma-associated herpesvirus (KSHV)-negative B-cell lymphoma with serosal spreading of the body cavity and lymphadenopathy: an autopsy case.

CD138-positive and Kaposi's sarcoma-associated herpes virus (KSHV)-negative B cell lymphoma with serosal spreading of the body cavity and lymphadenopathy is presented. Our lymphoma cells showed pleomorphic morphology and a clonal immunoglobulin gene rearrangement. Immunophenotypically, they lacked B- and T-cell-associated antigens but expressed strong membranous CD138 antigen along the serosa. Although our case was not conventional primary effusion lymphoma (PEL) because of the absence of KSHV and the presence of lymphadenopathy, its unique phenotype and serosal spreading were consistent with those of PEL. Our case suggests that, irrespective of KSHV infection, some pleomorphic B cell lymphomas with membranous CD138 expression show a peculiar serosal spreading.