Primary cutaneous diffuse large B-cell lymphoma, leg type

**Definition:** An aggressive primary cutaneous B-cell lymphoma, usually involving the lower leg. It is composed of a generally monotonous proliferation of immunoblasts, or less frequently centroblasts, with few admixed reactive cells. This type of lymphoma occurs most often in the elderly who present with rapidly growing tumours, usually on one or both legs. Dissemination to extracutaneous sites is frequent.