Solitary mycosis fungoides: a distinct clinicopathologic entity with a good prognosis: a series of 15 cases and literature review.

Background: 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.

Objective: 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.

Methods: 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.

Results: 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.

Limitations: This study was retrospective; follow-up data were not available in some cases and were only short term in others.

Conclusions: 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.