Syringotropic cutaneous T-cell lymphoma: an immunophenotypic and genotypic study of five cases.

There is uncertainty about the exact nosological relationship between mycosis fungoides, follicular mucinosis, syringolymphoid hyperplasia with alopecia (SLHA) and syringotropic cutaneous T-cell lymphoma (CTCL). We report the clinical, histological, immunophenotypic and genotypic characteristics of a series of five patients (three men and two women) with syringotropic CTCL. We also review the 15 cases of SLHA previously reported in the literature. We conclude that syringotropic CTCL is a distinct clinicopathological variant of mycosis fungoides which may present on its own with characteristic punctate erythema or more commonly in association with folliculotropic lesions. Syringotropic CTCL is characterized histologically by infiltration of sweat glands by atypical lymphocytes in association with syringolymphoid hyperplasia. Cases of SLHA represent a syringotropic form of CTCL in association with follicular involvement, and such cases need to be investigated using T-cell receptor gene analysis of both skin and blood. Only limited conclusions on prognosis can be derived from our preliminary data. However, a review of the literature suggests that the prognosis does not differ significantly from other types of mycosis fungoides of equivalent stage.