Primary cutaneous lymphomas: a study of 37 cases

A retrospective clinical, histologic, and immunohistochemical study was performed in 37 cases of isolated primary cutaneous lymphoma (PCL) (22 B and 15 T phenotype). Patients with epidermotrophic infiltrate (mycosis fungoides and Sézary syndrome) were excluded.

Patients with PCL were selected according to strict criteria: isolated cutaneous involvement for at least 6 months and a negative exhaustive study of possible spread. Lesions were either limited to a single cutaneous region or were disseminated, involving at least two nonadjacent regions. The diagnosis was confirmed histologically, and an immunohistochemical study was performed.

On the basis of the new Willemze classification for prognostic criteria, this study showed similarities between lymphomas of B and T phenotype in clinical features, therapeutic response, course, and overall prognosis. The clinical lesion was usually an erythematous nodule associated, or not, with an infiltrated layer and generally limited to a single cutaneous region. PCLs were highly sensitive to nonaggressive treatment, showing complete or more than 50% partial remission in all cases.

The overall prognosis for these lymphomas was good, even for disseminated cutaneous forms. Patient survival at 48 months was 78% for T and 89% for B phenotype. In the latter group, the prognosis was comparable for CD30+ and CD30- T lymphomas; however, the course of PCL involved frequent cutaneous relapses, particularly with the disseminated forms, raising the problem of adjuvant treatment after complete remission was obtained. Extracutaneous involvement was rare, but always indicative of poor prognosis.