Unilesional mycosis fungoides: clinical, microscopic and immunophenotypic features.

Seven cases are reviewed in which the histologic and immunohistologic features were those of mycosis fungoides, although the patients presented with solitary lesions which did not recur after local therapy (excision in six, radiotherapy in one), with follow-up of 10 months to 18 years. Immunophenotypic staining of paraffin-embedded tissue revealed a predominant T-lymphocyte proliferation in all cases, None of the four cases studied for BER-H2(Ki-1) were positive, in contrast to the "activated" types of spontaneously regressing lymphoid lesion, lymphomatoid papulosis and "Ki-1" lymphoma. Electron microscopy in one case demonstrated the highly convoluted nuclei of the T cells within the infiltrate. These seven cases represent examples of unilesional mycosis fungoides in which the disease has not recurred after therapy, despite features indistinguishable from those of typical generalised mycosis fungoides-type of cutaneous T-cell lymphoma.