Authors report here on a case presenting as B-CLL and complicated with cutaneous infiltration involving the legs and the trunk a year later. Immunohistochemic analysis and the immunoglobulin heavy chain gene rearrangement confirmed cell invasion into the skin identical with the underlying disorder. After failure of conventional chemotherapy, interferon alpha 2b therapy has been started with satisfactory result. Few cases presenting cutaneous infiltration in the course of B-CLL has already been reported in the literature. Secondary cutaneous B-cell lymphoma represents an entity of the poorest prognosis in comparison with primary cutaneous form treated with conventional therapy as well as with lymphomas lacking skin manifestations. Interferon alpha 2b therapy cleans up the skin and yields a favourable survival so it's introduction recommended in this entity. Authors summarise the characteristics of secondary cutaneous B-cell lymphomas on the basis of literature survey. According to authors investigations histidine decarboxylase activity was found to be absent from the lymphocytes infiltrating the skin in contrast to those remaining in the circulation. This seems to be a newly recognised feature of these cells. The changing character of the disease raises the possibility of an altered gene expression pattern of the cells invading the skin. Authors summarise data from the literature concerning suspected molecular mechanism of tissue invasion.