Primary cutaneous T-cell-rich B-cell lymphoma in a zosteriform distribution associated with Epstein-Barr virus infection.

T-cell-rich B-cell lymphoma (TRBL) is a lately recognized B-cell lymphoma variant characterized by a minor population of neoplastic B cells existing in a background of predominant polyclonal T cells. We report an 86-year-old man with primary cutaneous TRBL associated with Epstein-Barr (EB) virus infection. Clinically, palpable scaly erythemas were distributed in a zosteriform pattern on the right abdomen. Histologically, massive cellular infiltrates were located in the upper- and mid-dermis. Higher magnification showed that the cellular infiltration was composed mainly of abnormal mononuclear, large lymphoid cells with clear cytoplasm and scattered mitoses and small lymphocytes, which represented in excess of 75% of all the infiltrating cells. Immunohistochemical staining revealed that the large cells were positive for the B cell marker, CD20, but negative for the T cell marker, CD3. On the other hand, the small cells were positive for CD3, but negative for CD20. Polymerase chain reaction (PCR) revealed EB virus DNA in the skin lesion. Primary cutaneous TRBL has only been reported in 15 cases worldwide. To our knowledge, this is the first case of primary cutaneous TRBL in a zosteriform distribution reported in the literature and the second case of primary cutaneous TRBL associated with the EB virus infection. We postulate that the EB virus may be a contributory pathogenetic event leading to monoclonal B-cell proliferation.