Ectodermal structures within the uterine cervix and vagina: report of a series of cases.

Ectodermal structures, in the form of sebaceous glands and hair follicles, are extremely rare within the cervix and vagina. We describe the clinicopathologic findings in 11 cases (10 cervix, 1 vagina) with a view to exploring the histogenesis of this unusual phenomenon. The cases occurred in patients aged 33 to 71. In 10 of the cases, sebaceous glands were present that were associated with hair follicle-like structures in 3 cases forming pilosebaceous units. In the other case, hair follicle- and sweat gland-like structures were present; the latter have not been previously described in the cervix. The ectodermal structures were usually either attached to the basal layer of the surface squamous epithelium or lay "free" within the superficial stroma, although in 1 case sebaceous glands were located within the squamous epithelium. The squamous epithelium overlying the ectodermal structures typically exhibited hyperkeratosis. Although we were unable to definitively resolve the debate as to whether ectodermal structures within the cervix and vagina represent misplaced embryonal tissue and a true heterotopia or a "metaplastic" process, we favor the latter as a response to prolonged irritation or chronic injury.