Malignant Lymphomas of the Skin - Diagnosis and Therapy of Primary Cutaneous B-Cell Lymphomas

Primary cutaneous B-cell lymphomas (PCBCL) represent extranodal non-Hodgkin's lymphomas of mature B lymphocytes with the skin as the target organ and the site to proliferate. They show a wide range of clinical and histological features. Approximately 22% of cutaneous lymphomas (CL) are made up of cutaneous B-cell lymphomas (CBCL) and 73% of cutaneous T-cell lymphomas (CTCL). The remaining less than 10% are classified as rare subtypes of CL. The incidence of CL remains increasingly and is estimated at one incidence per year and 100000 inhabitants. The diagnosis of PCBCL is usually based on clinical, histological and immunohistochemical investigations. But the findings do not always allow an unambiguous diagnosis. Especially early stages of a PCBCL often resemble benign inflammatory skin diseases, both clinically and histologically. Due to the heterogeneity of PCBCL including different biological potencies, ranging from an indolent to a fulminant and fatal course, a distinct diagnosis is essential. Therefore, the correlation of dermatohistology, in combination with immunohistochemistry and molecular biology, plays a crucial role.