A Case of Papillary Eccrine Adenoma: Immunohistochemical Study

ABSTRACT

A case of papillary eccrine adenoma on the right hand of a 84-year-old woman is reported. The tumor was 1 cm in diameter, occupying the whole thickness of the dermis. Histologically, the tumor was composed of dilated tubules of various sizes with intraluminal papillary projections, and was surrounded by a fibrous stroma. An immunohistochemical study revealed that the proliferating tubules were composed of the outermost layer of alpha-smooth muscle actin-positive and the inner layer of keratin 14-negative cells. This antigen expression pattern was comparable to that of the normal eccrine secretory coil, which indicates that the tumor differentiated toward the secretory coil of an eccrine sweat gland.