Large B-cell lymphoma of the leg: Clinical and pathologic characteristics in a North American series

Background: Large B-cell lymphoma (LBCL) of the leg is an uncommon subset of primary cutaneous B-cell lymphoma that has been described in a series of European patients. Objective: Our purpose was to evaluate the clinical manifestation, diagnostic histopathology, immunophenotype, clinical course, and response to treatment of LBCL of the leg. Methods: We conducted a retrospective case series of 3 patients with primary LBCL of the leg. Results: The 3 elderly patients presented with progressive erythematous nodules on bilateral or unilateral lower extremities. All 3 patients had pre-existing peripheral edema or peripheral vascular disease. Histopathologic examination of the nodules showed dense lymphocytic infiltrates composed predominantly of large dysplastic lymphocytes that marked as B cells (CD20⁺). In 2 cases, the neoplastic cells were BCL-2 positive. All patients responded to initial therapy with localized electron beam radiation and chemotherapy but had disease progression. One patient had a complete and durable second response to anti-CD20 monoclonal antibody (rituximab). Conclusions: The patients described have similar clinical and histopathologic features to those previously described. There may be an association between LBCL and pre-existing lower-extremity vascular disease. Treatment of LBCL is difficult, but 1 patient responded well to systemic anti-CD20 monoclonal antibody.