Lymph node histopathologic findings in cutaneous T-cell lymphoma. A prognostic classification system based on morphologic assessment.

The histopathologic features of 251 lymph nodes obtained from 200 patients with various clinical expressions of cutaneous T-cell lymphoma (mycosis fungoides and Sezary syndrome) were reviewed retrospectively. Lymphomatous involvement, defined as partial or complete effacement of lymph node architecture by malignant cells, was identified in 89 specimens (35%) and was characterized by morphologic variability from case to case. The involved specimens were classified into four major histologic subtypes according to the morphologic appearance of the malignant cells in a manner analogous to a modified Rappaport classification of diffuse non-Hodgkin's lymphomas. Although lymph node involvement was associated with a poor prognosis regardless of histologic subtype, the survival of patients with small cell (cerebriform) subtype was found to be significantly better (median survival time, 40 months) than other subtypes (median survival time, 20 months), possibly because this type of involvement sometimes preceded the development of the more aggressive mixed and large cell subtypes. Dermatopathic lymphadenopathy compared to other reactive patterns had no special prognostic importance other than its more frequent occurrence in black patients and in patients with more extensive skin involvement.