CC chemokine receptor 4-positive diffuse large B-cell lymphoma involving the skin: a case report.

Leukocyte trafficking is critically regulated by chemokines and their receptors. The involvement of the skin in certain subsets of T-cell malignancies has been explained by the discovery of an interaction between the thymus and activation-regulated chemokine (TARC), which is abundant in the skin, and its receptor, CC chemokine receptor 4 (CCR4), which is expressed in the tumor cells. We describe a diffuse large B-cell lymphoma (DLBCL) that showed CCR4 expression with involvement of the skin. A 55-year-old man presented with a giant skin ulcer of the right axilla, and his disease was diagnosed as DLBCL. Further clinical examination revealed an ulcerated gastric lymphoma lesion. Immunohistochemical and real-time reverse transcriptase-polymerase chain reaction analyses showed that the tumor cells were positive for CCR4, and TARC was expressed at extremely high levels in the lymphoma-affected skin. These observations suggest that the interaction between CCR4 and TARC played a significant role in the involvement of the skin in this case, similar to what has been observed in certain subsets of T-cell malignancies. To the best of our knowledge, this report is the first of a CCR4-positive B-cell lymphoma. The present case provides new insights into the pathogenesis of skin involvement in B-cell lymphomas.