Unilesional mycosis fungoides: a distinct entity.

Four cases of solitary lesions showing the histologic features of mycosis fungoides are described. Three patients had an erythematous scaling plaque, whereas the fourth had a solitary nodule. The lesion was located on the arm in two patients, on the foot in one patient, and on the back in one patient. No preceding factors were noted, and no lymphadenopathy or other significant illness was found on examination. Histologic examination demonstrated features of a cutaneous T cell lymphoma with epidermotropism. Monoclonal markers on frozen and paraffin sections revealed a predominant T cell infiltrate. Three patients were treated with local excision. The remaining patient was treated with radiotherapy. The lesions have not recurred, and no new lesions have developed after individual follow-up of 7 months, 7 1/2 months, 13 years, and 18 years. These cases appear to be unique reports of solitary mycosis fungoides behaving in a biologically benign manner. The relationship to Woringer-Kolopp disease and lymphomatoid papulosis is discussed.