Unusual clinicopathological presentation of primary cutaneous diffuse large B-cell lymphoma, leg type, with multiple nodules and widespread garland-like lesions.

We present a case of primary cutaneous diffuse large B-cell lymphoma, leg type, with an unusual clinical picture. A 41-year-old man presented with a 2-year history of slowly progressive plaques, nodules, and garland-like patches on his chest, right upper arm, and back. Complete staging investigations revealed no extracutaneous involvement. Histological examination of a nodule revealed a diffuse nonepidermotropic infiltrate mainly composed of large blast cells with features of immunoblasts and centroblasts and spindle cells seen at the periphery of the infiltrate. Histological examination of a garland-like lesion showed perivascular infiltrates composed predominantly of small lymphocytes admixed with only occasional large blasts. The blasts from the nodule and garland-like lesions and spindle cells identified in the nodule exhibited an identical phenotype: they stained positively for CD20, CD79a, and bcl-2 and tested negative for bcl-6, CD5, CD10, and TdT. CD35 revealed no networks of follicular dendritic cells. Widespread garland-like lesions are not a typical feature of primary cutaneous diffuse large B-cell lymphoma.