Hidrocystoma (also known as cystadenoma,[1] a Moll's gland cyst,[1] and a sudoriferous cyst[1]) is an adenoma of the sweat glands.

[2]: 787 Hidrocystomas are cysts of sweat ducts, usually on the eyelids.

Hidrocystomas usually arise from apocrine glands.

A type of hidroadenoma that arises from eccrine glands is uncommon.

Other related conditions on the eyelids include chalazion (a granulomatous reaction to sebaceous glands on the eyelid), lacrimal duct cysts (cysts related to tear ducts), and nasolacrimal duct cysts (the nasolacrimal duct drains tears into the nose via a punctum on the lower eyelid).