POSTTRANSPLANTATION PLASMA-CELL DYSCRASIAS

Background. Lymphoproliferative disorders that occur in patients recei ving cyclosporine for immunosuppression after solid organ transplantat ion typically are B-cell neoplasms associated with Epstein-Barr virus (EBV), which may be polyclonal or monoclonal in origin. Although these tumors may have partial B-cell differentiation, (manifested as plasma cytoid features), terminal differentiation to plasma cells that secret e a monoclonal immunoglobulin is rare. The case of a patient who devel oped a posttransplantation lymphoproliferative disorder that was compo sed of multiple plasmacytomas located in the abdomen and urinary bladd er after liver transplantation is presented. The patient also had high levels of an immunoglobulin-GK monoclonal paraprotein. Methods. The p lasmacytoma was examined for the presence of EBV by both polymerase ch ain reaction and in situ hybridization, and the possibility of a codon -12 mutation in the ras gene was investigated by digestion of DNA ampl ification products with the HpaII-restriction edonuclease. Results. Ep stein-Barr virus genomes were demonstrated by DNA amplification of seq uences in the long, internal, direct repeat region, and in situ hybrid ization showed expression of EBV RNA transcripts that annealed to an E BER-1 probe. Immunohistochemistry showed clonally restricted expressio n of K light chains but failed to reveal evidence of expression of the latent membrane protein 1 encoded by EBV. Mutations of codon-12 in th e H-ras gene were not detected. Conclusions. Resolution of the tumor a nd the paraprotein after radiation and reduction of immunosuppression indicates that terminal plasmacytic differentiation does not necessari ly portend an unfavorable prognosis, even in a clonal lesion.