Mycosis fungoides with a CD56+ immunophenotype.

We report 3 cases of mycosis fungoides (MF) with a CD56+ cytotoxic immunophenotype. Each patient presented with a different clinical phenotype: one exhibited limited poikilodermatous patches (skin stage T1); one, widespread hypopigmented lesions (skin stage T2); and one, poikiloderma with a single cutaneous tumor (skin stage T3). MF was confirmed both histologically and by the presence of a T-cell receptor clone in lesional skin in all cases.