Lymphomatoid papulosis with a natural killer-cell phenotype.

Abstract

Lymphomatoid papulosis (LyP) is defined as a recurrent self‐healing papulonodular eruption with the histological features of a (CD30+) cutaneous T‐cell lymphoma. The atypical cells usually have a CD3+/–, CD4+/–, CD8–, CD30+, CD56– T‐cell phenotype. We report an unusual case of LyP, in which the atypical cells expressed a CD3–, CD4–, CD8–, CD30+, CD56+ phenotype. Detailed phenotypic and genotypic analysis confirmed that these cells had a natural killer (NK)‐cell phenotype. Lymphomas with an NK‐cell phenotype usually have a poor prognosis. However, the waxing and waning of papular lesions for more than 20 years and the excellent response to low‐dose oral methotrexate in this patient suggest similar clinical behaviour to LyP cases with a T‐cell phenotype.