Eccrine syringofibroadenoma: report of a case and analysis of cytokeratin expression.

Eccrine syringofibroadenoma (ESFA) is a rare disorder which shows differentiation toward the eccrine sweat apparatus. There is a controversy concerning the pathogenesis and precise differentiation of this tumor. We report a case of ESFA and its differentiation pattern by an analysis of cytokeratin expression. Using paraffin-embedded materials, histopathological and immunohistochemical studies were performed. Staining patterns of the luminal, peripheral, and inner cells of the tumor strands closely matched or mimicked those of the luminal, outer and intermediate cells of the normal eccrine dermal duct, respectively. The case of ESFA reported revealed a pattern of differentiation suggestive of an eccrine duct origin.