Solitary mycosis fungoides: A distinct clinicopathologic entity with a good prognosis

Abstract

Mycosis fungoides (MF) is the most common cutaneous T-cell lymphoma (CTCL), accounting for almost 50% of all primary cutaneous lymphomas. The occurrence of solitary lesions, which are clinically and histopathologically indistinguishable from classic MF has been described. We describe 15 cases of solitary MF and discuss the relationship to classic MF, "reactive" processes and to other, rarer forms of CTCL that may present with solitary lesions. We conducted a retrospective chart review and a PubMed search to identify all reported cases of solitary MF to date, as well as information about other CTCLs presenting as a solitary lesion. Fifteen patients were identified. Follow-up data were available on 10 patients with a median follow-up of 10 months (range, 1 to 48 months). Clinical, pathological, immunocytochemical, and molecular-genetic features were analyzed. Five cases were diagnosed as folliculotropic MF (FMF). Of the 10 cases with follow-up, 2 were treated with topical steroids, 2 were completely excised, 5 received radiotherapy, and 1 received tacrolimus. One hundred twenty-eight cases of solitary MF were identified in the literature and reviewed for commonalities to and differences with our cases and other CTCLs. This study was retrospective; follow-up data were not available in some cases and were only short term in others. Solitary MF appears to have a good prognosis. In lesions that are not completely excised, curative radiotherapy can be used. Long-term follow up is advised.