Primary cutaneous B-cell lymphomas: then and now.

In the past, concepts of cutaneous lymphomas were based on careful clinical and classical histopathological descriptions. Most primary cutaneous B-cell lymphomas (pCBCL) were designated as lymphosarcoma, follicular lymphoma, histiocytic lymphoma, reticulum-cell sarcoma or skin reticuloses. Today, pCBCL are classified as a fully recognized and well-defined group of extranodal lymphomas according to the criteria of the World Health Organization-European Organization for Research and Treatment of Cancer classification. Better understanding of the mechanisms of the pathogenesis in pCBCL will hopefully stimulate investigative research and provide further improvement of diagnosis and treatment.