Nonfamilial Unilateral Linear Eccrine Syringofibroadenoma of the Plantar Surface: A Diagnostic Consideration in Acral Eccrine Proliferations

ABSTRACT: Eccrine syringofibroadenoma (ESFA) is an uncommon benign adnexal neoplasm characterized by eccrine ductal differentiation and a distinctive reticulated architectural pattern. The nonfamilial unilateral linear subtype is exceedingly rare and may pose diagnostic difficulty, particularly in acral locations. We describe a long-standing unilateral linear plantar lesion in a middle-aged woman. Histopathological examination revealed anastomosing epithelial cords extending from the epidermis into a fibrovascular stroma, with associated eccrine duct-like structures, consistent with ESFA. Recognition of these characteristic features is essential to distinguish ESFA from other reactive, infectious, and neoplastic eccrine proliferations encountered in dermatopathology practice.