Onychodystrophy and tumor-stage mycosis fungoides confined to a single digit: report of a case and review of nail findings in cutaneous T-cell lymphoma.

Mycosis fungoides is often considered one of the great disease imitators presenting with a wide variety of clinical manifestations. We present a case of tumor-stage mycosis fungoides involving a single digit clinically presenting with diffuse swelling of the digit and onychodystrophy. Histologic findings included a reticular dermal lymphocytic infiltrate with increased ratio of CD4:CD8 cells. The patient was treated with radiation resulting in complete resolution. Nail involvement with mycosis fungoides has been scarcely reported, but when present ranges from 20-nail dystrophy to yellow discoloration. The disease often involves most of the nails when present.