Differentiation between lymphadenosis benigna cutis and primary cutaneous follicular center cell lymphomas. A comparative clinicopathologic study of 57 patients.

The authors report the clinical and histologic features of 22 cases of lymphadenosis benigna cutis (LBC) and 35 cases of primary cutaneous follicular center cell (FCC) lymphoma. The differential diagnostic accuracy of criteria generally used for differentiating between benign and malignant cutaneous lymphoid infiltrates was evaluated. The clinical and histologic findings in these two groups showed many similarities. Except for a characteristic clinical presentation of patients with a primary cutaneous FCC lymphoma on the trunk, there was no single clinical or histologic criterion that reliably differentiated between both conditions in all cases. Follow-up data showed that only a small number of patients of the malignant group developed (four of 35 cases) or died of (two of 35 cases) systemic lymphoma. The favorable prognosis of this type of cutaneous lymphoma implies that lack of systemic lymphoma after a five-year follow-up cannot be used as a diagnostic criterion in retrospective studies.