Papillary eccrine adenoma: an electron microscopic study.

A case of papillary eccrine adenoma was studied by electron microscopy. Dilated ducts that contained granular eosinophilic material, often associated with intraluminal papillary projections were observed. The ductlike structures were composed of basal and luminal cells. Within the luminal cells there were intracytoplasmic cavities, but neither secretory granules nor glandular structure were observed. On the basis of our observations, papillary eccrine adenoma appears to differentiate toward ductal structures of the eccrine sweat apparatus.