Unilesional mycosis fungoides - A study of seven cases

Background Unilesional mycosis fungoides (MF) is a rare variant of cutaneou s T-cell lymphoma (CTCL), characterized by a solitary lesion clinically and by histopathological features indistinguishable from those of MF, and typi cally having a benign course. Objective: To describe the clinicopathologica l features of a series of patients with unilesional NIF. Methods: The recor ds of cases of unilesional MF identified during a In-year period in two med ical departments were reviewed. Results: There were 7 patients: 6 males, 1 female; mean age at the time of diagnosis: 32 years; age range: 12-58 years ; 3 were below the age of 18 years. The mean pretherapy followup period was 9 years (range: 2-20 years). In 5 patients, the eruption consisted of a ch aracteristic patch or plaque of MF located on the trunk or upper extremity; in 2 it was atypical-in 1, a hypopigmented patch, and in I, a plaque indis tinguishable from MF-associated follicular mucinosis. Histopathologically a ll the lesions exhibited features characteristic of MF, with CD3+ lymphoid cells. in 6 cases (with available fresh frozen tissue) there was a predomin ance of CD3+ CD4+ cells; in 1 of 5 there was deletion of CD7, and in 3 of 5 there was an overexpression of IL-2 receptor. T-cell receptor gamma gene r earrangement was found in 1 of 4 cutaneous lesions tested; in 2 cases it wa s found in the blood but not in the skin. Treatment modalities included loc alized electron beam, excision, topical nitrogen mustard or topical steroid s and sunbathing, resulting in all cases in a sustained complete clinical r esponse. In 1 patient, however, there were 2 local recurrences and in yet a nother patient there was distant cutaneous spread 3.5 years after therapy. Conclusions: Unilesional MF is a rare variant of CTCL, has heterogeneous cl inical manifestations and can affect any age group, including children. The histopathological and immunophenotypical features are in general indisting uishable from those observed in multilesional MF. Although it is a unifocal event, there may occasionally be cutaneous spread with the appearance of n oncontiguous lesions, even a long time after therapy. Whether all cases rep resent minimal-stage IA MF or whether some are actually T-cell pseudolympho ma remains to be clarified. Copyright (C) 2000 S. Karger AG, Basel.