A 68-year-old man had a solitary, eczematiform lesion of two years' duration on the digital dorsal surface of his right foot. Despite its innocuous appearance, the lesion showed histologic characteristics of advanced, plaque-type mycosis fungoides. The patient's clinically benign yet histologically malignant disease manifestation is discussed. The distinction between localized mycosis fungoides and Woringer-Kolopp disease is also reviewed.