CD4+, CD56+ mycosis fungoides: case report and review of the literature.

This case report details an 85-year-old woman who presented with mycosis fungoides (MF), clinical stage 1A. Bilateral lesions on the upper thighs were responsive to topical steroid therapy. Biopsies showed band-like dermal infiltrates of medium-sized lymphocytes with marked epidermotropism, including large intraepidermal lymphocytes with nuclear convolutions, consistent with MF. Immunohistochemical staining revealed that the lesional cells were CD56+, but unlike the case in previous reports of CD56+ MF, they also expressed CD4 and T-cell intracellular antigen 1 and did not express CD8. To our knowledge, this is the first description of a case of MF with a CD4+, CD8-, CD56+, T-cell intracellular antigen 1-positive immunophenotype. At 85 years of age, the patient is older than all previously described patients with CD56+ MF. Despite an immunophenotype observed more commonly in aggressive forms of cutaneous T-cell lymphoma, the clinical presentation is that of typical MF. The patient presented with limited disease and after 12 months of follow-up has not progressed beyond stage 1A.