[Mycosis fungoides presenting as annular erythema].

INTRODUCTION: Mycosis fungoides is a lymphoma, the classical clinical form of which involves erythematosquamous lesions. However, it can present various atypical aspects: hyper pigmentation or hypo pigmentation, suggestive of pyoderma gangrenosum or ichtyosis. We report a case of mycosis fungoides, unusual in its presentation in the form of centrifugal annular erythema. OBSERVATION: A 78 year-old man had developed a parapsoriasis in plaques for more than 20 years. In May 2002 he consulted because of the recent infiltration of one of the plaques, without concomitant pruritus. The clinical examination revealed 3 lesions of the popliteal groove of the right groin and the left cheek suggestive of centrifugal annular erythema. Histology, revealing Pautrier microabscesses, was compatible with the diagnosis of mycosis fungoides. Evolution was marked by the spontaneous regression of the plaque on the face and remission of the other two plaques after local treatment with chloromethin and topical corticosteroids. Nevertheless, new plaques appeared despite continued treatment, combined with PUVA therapy sessions. DISCUSSION: When searching the literature, we only found one other case of mycosis fungoides, the clinical aspect of which was a centrifugal annular erythema, but in which the histological examination confirmed the diagnosis of mycosis fungoides. Our case report is also unusual in the clinical regression of the lesion on the face, without treatment; this has only been reported in two cases. Mycosis fungoides can appear in various clinical forms. The centrifugal annular erythema form is rare, but this diagnosis should be evoked.