Pityriasis lichenoid-like mycosis fungoides

Abstract

Sir, Mycosis fungoides is a primary cutaneous T–cell lymphoma, secondary clonal proliferation of mature skin-homing T cells, mostly CD4-positive, with a predilection for involving the epidermis. It is an indolent lymphoma that progresses over several years and represents 50% of primary cutaneous T-cell lymphomas [1]. Its clinical presentation is variable, thus leading to several clinical variants. Herein, we describe a rare variant of mycosis fungoides: pityriasis lichenoid-like mycosis fungoides. A 45-year-old female was referred to our department with a papular rash evolving for the last year without regression. The patient had a history of breast carcinoma in complete remission for two years. A clinical examination revealed erythematous, scaly, non-itchy papules covering the entire body but sparing the face (Figs. 1 and 2). There was no scalp involvement or associated lymphadenopathy. Based on the clinical presentation, the suggested diagnosis was pityriasis lichenoid. A histological examination revealed Pautrier’s microabscesses, atypical lymphocyte infiltration along the basal layer and papillary dermis, and prominent epidermotropism (Fig. 3). There was pilotropism without mucin. Besides, hyperkeratosis with focal parakeratosis and perivascular infiltrate were noted. An immunohistochemical analysis revealed infiltrates of T cells expressing CD3, CD2, CD5, and a predominance of CD4-positive T cells in the epidermis compared to CD8-positive T cells. CD7 and CD30 were, however, negative. These findings were consistent with pityriasis lichenoid-like mycosis fungoides. The patient was classified as a IB stage and received UVB phototherapy with good progress.