Epidermotropic cutaneous B-cell lymphoma mimicking mycosis fungoides.

Cutaneous involvement by B-cell lymphoma is often secondary to systemic disease. Primary cutaneous B-cell lymphomas are less common, and patients generally have an excellent prognosis. We present a patient with cutaneous B-cell lymphoma with clinical and histologic features mimicking mycosis fungoides. Although the patient was initially misdiagnosed as having a T-cell lymphoma, immunophenotypic studies demonstrated that this was a B-cell lymphoma.