Eccrine hidrocystoma of the external ear canal: a case report.

Eccrine hidrocystomas are essentially sweat gland retention cysts located in the dermis. Clinically, an eccrine hidrocystoma presents as a small, translucent cystic swelling (often having a bluish hue), and measuring from 1 to 3 mm in diameter. The clinical and histopathological features of an eccrine hidrocystoma of the external auditory canal are presented, and the morphologic differences between an eccrine and an apocrine hidrocystoma are discussed.