Primary cutaneous large B-cell lymphomas of the legs - A distinct type of cutaneous B-cell lymphoma with an intermediate prognosis

Background and Design: Primary cutaneous follicular center cell lymphomas represent a distinct type of cutaneous B-cell lymphoma, clinically characterized by localized skin lesions on the head or trunk and an excellent prognosis. Histologically similar lymphomas may occur on the legs. The clinical behavior of this group is still undefined, and controversy exists whether these lymphomas should be classified as follicular center cell lymphoma or B-immunoblastic lymphoma. We reviewed the clinical, histologic, and follow-up data of 18 patients with primary cutaneous large B-cell lymphoma of the legs. Results: Primary cutaneous large B-cell lymphoma of the legs generally occurred in elderly patients (median age at diagnosis, 76 years), in particular women (male-female ratio, 7:2), and preferentially affected the lower legs (14 of 18 patients). Radiotherapy and/or systemic polychemotherapy resulted in complete remissions in 16 of 17 patients. Follow-up data demonstrated estimated 2- and 5-year survival rates of 77% and 58%, respectively, Histologic evaluation showed diffuse dermal infiltrates with variable proportions of centroblasts (large noncleaved cells), large centrocytes (large cleaved cells), and B immunoblasts. Seventeen of 18 patients were diagnosed as having primary cutaneous follicular center cell lymphoma; only 1 patient, whose histologic examination showed more than 30% immunoblasts, was diagnosed as having B-immunoblastic lymphoma. Conclusions: Primary cutaneous large B-cell lymphoma of the legs is a distinct clinicopathologic entity that mainly affects elderly patients and has an intermediate prognosis. Although most cases have a follicular center cell origin, primary cutaneous large B-cell lymphoma is proposed as the most appropriate term for this type of cutaneous lymphoma.