Anogenital "sweat" glands. Histology and pathology of a gland that may mimic mammary glands.

A new variant of cutaneous glands is described that occurs in the anogenital region, with its highest concentration in the interlabial sulcus of the vulva. The glands are characterized by a wide coiled tube from which originate acini, diverticula, and short branches; a lining of a compact simple columnar epithelium with prominent cytoplasmic snouts protruding into the lumen; and a broad mantle of loose fibromyxoid to dense collagenous connective tissue. Occasionally, true lobuli are formed resembling those of mammary glands. A close relationship to eccrine glands was evidenced by intermediate variants and the occasional observation of typical eccrine segments in otherwise characteristic anogenital glands. The glands revealed periodic changes of epithelium and stroma. Their strict localization around the derivatives of the embryonic cloacal entrance suggests a possible role in sexual functions. Their characteristic histology links and explains a series of disorders of the anogenital region in women (including functional vulvar mammary glands after pregnancy, fibrocystic disease, fibroadenoma, hidradenoma papilliferum, and some cases of adenocarcinoma, including Paget's disease) and in men [including fibroadenoma or apocrine cystadenoma, and cases of Paget's disease].