Oral mycosis fungoides: report with immune profile.

Mycosis fungoides (MF) is a cutaneous T-cell lymphoma that uncommonly involves the oral mucosa. Oral MF is an indication of systemic progression and is often associated with an unfavorable outcome. Any oral mucosal site may be affected. This report describes a case of MF involving the hard palate of a 64-year-old woman with confirmed skin MF. The histology showed intra- and subepithelial atypical lymphocytes. Immunohistochemistry on the tissue sections showed that the CD4:CD8 ratio was high (5.8:1) and the CD8:CD3 ratio was low (0.16:1). FoxP3(+) (forkhead box P3-positive) regulatory T cells were conspicuous within the infiltrate, but few interleukin-17 cells were observed. This report is the first to describe a detailed immune profile in oral MF.