Mycosis fongoïde papuleux

Abstract

Mycosis fungoides (MF) is the most common type of cutaneous T-cell lymphoma. A new form of incipient MF has recently been described: papular MF. Herein, we report a case and propose a literature review. A 63-year-old man presented with erythematous and non-pruritic papular lesions of the trunk. The general examination was unremarkable. A skin biopsy showed moderately dense epidermotropic lymphocytic infiltration consistent with MF. Screening for CD30 was negative. Treatment with an extremely potent corticosteroid (clobetasol, one application per day) seemed effective, with almost complete disappearance of the lesions. Many clinical variants of the initial stages of MF have been described, one of the most recent of which is papular mycosis fungoides (PMF), of which 10 cases are reported in the literature. PMF begins clinically with an erythematous, non-pruritic and chronic papular rash that is not associated with the classic erythematous-squamous lesions of incipient MF. There appears to be no predominance of gender, and the age of onset ranges from 31 to 63 years. Histological examination of the PMF lesions revealed an epidermotropic subepidermal infiltrate composed predominantly of CD4+T-cells. The prognosis appeared good with the treatments conventionally used for incipient MF. PMF is likened to a form of incipient MF with a good prognosis. Associated classic MF lesions comprising erythematous-squamous plaques have been described as the condition progresses. Differential diagnoses include pilotropic MF, pityriasis lichenoides chronica, pityriasis lichenoides varioliformis acuta, and especially type B lymphomatoid papulosis, the histopathological findings of which may be close to PMF. Papular MF would appear to be a papular variant of incipient MF with a good prognosis. However, it is necessary to obtain clinical and disease progression data for a greater number of patients in order to better characterize this entity.