Cutaneous B-Cell Lymphoma.

Primary cutaneous B-cell lymphomas are non-Hodgkin lymphomas that present in the skin without evidence of extracutaneous involvement at diagnosis. There are 3 types of primary cutaneous B-cell lymphomas: primary cutaneous marginal zone lymphoma, primary cutaneous follicle center lymphoma, and primary cutaneous diffuse large B-cell lymphoma, leg-type. Because it is most frequently diagnosed on skin biopsy, intravascular large B-cell lymphoma is commonly included with pcBCL. A complicating factor in diagnosing primary cutaneous B-cell lymphomas is that they can appear histologically identical to their extracutaneous counterparts. This review summarizes the clinical presentation, histopathology, evaluation, treatment, and differential diagnosis of these lymphomas.