PRIMARY CUTANEOUS B-CELL LYMPHOMAS IN JAPAN - A REPORT OF 3 CASES ANDA COMPARISON OF JAPANESE AND WHITE PATIENTS

Background: In contrast to cutaneous T-cell lymphoma, primary cutaneou s B-cell lymphomas (pCBCL) are rare in Japan. Thus there have been no reports in the English literature that analyze Japanese pCBCL cases in detail. Objective: We describe three additional Japanese cases of pCB CL and review the Japanese literature to compare their clinical featur es and prognoses with those in cases that involve white persons. Metho ds: In our three cases, we performed immunohistochemical and how cytom etric analyses to determine the phenotypes of tumor cells. Genotypic a nalysis was also conducted by Southern blotting. In addition, we revie wed 43 cases of pCBCL reported in Japan. Results: In our three cases o f pCBCL, the lack of systemic involvement indicated that they were pri mary cutaneous tumors. One of our cases, which had a poor prognosis, l acked both HLA-DR and CD44 phenotypes, which are usually observed in t he diffuse large-cell type of pCBCL. We found three major differences between the reported Japanese cases including ours and the cases that involved white persons: (1) histologically, the diffuse type was prese nted in 79% of lesions of less than 12 months' duration in the Japanes e cases but in only 9% of lesions in white persons; (2) chemotherapy w as more frequently selected in the Japanese cases (51%), whereas radio therapy was used more frequently in white cases (71%); and (3) the dea th rate from pCBCL was much higher in Japanese (16%) than in white (2% ) persons. Conclusion: pCBCL in Japanese persons seems to be different from that in white persons in frequency, in histoarchitectural growth pattern, and in prognosis.