HIDRADENOMA

HIDRADENOMA, hidradenoma (from Greek hidros-sweat and aden-gland), or hydradenoma, or syringoma, is a rarely occurring tumor of sweat glands. It is observed most frequently on the face, sometimes on the lips (even where sweat glands are normally absent), on the extremities, in the navel area, and on the vulva. Hidradenoma has the appearance of soft papule-like, well-defined formations about 2-5 mm in size, which rarely reach larger dimensions (for example, the size of a child's head); sometimes they are multiple. A considerable portion of hidradenomas is a congenital condition and is described as a variety of birthmarks. Upon microscopic examination, hidradenoma is found to have the structure of an adenoma (see). The glandular vesicles are lined by either one or two layers of cylindrical epithelium. Due to the cystic expansion of the gland lumens, pictures of the so-called hydrocystoma (see) or syringocystoma type may arise, and when there are papillary growths in these cysts, they are referred to as papillary hidradenomas. In addition to ordinary hidradenomas originating from mature sweat glands, adenoma hidradenoides is also distinguished, which occurs even more frequently and differs in that the tumor originates from rudimentary sweat glands or from the surface epithelium. Cases of hidradenoma transitioning to adenocarcinoma have been noted. Treatment is surgical.