Squamous metaplasia of the endometrium associated with HPV 6 and 11

Although uncommon in the endometrium, squamous metaplasia, dysplasia, and squamous carcinoma have been observed. Associated human papillomavirus (HPV) infection is also unusual, due at least in part to the fact that HPV requires specific characteristics of the target epithelium for infectivity. We report a case of extensive squamous metaplasia with focal low-grade squamous intraepithelial neoplasia of the endometrium coexistent with low-grade cervical intraepithelial neoplasia and an invasive squamous carcinoma of the vagina. In situ hybridization studies revealed HPV types 6 and 11 in both the cervical and endometrial lesions. This is the first report to date to demonstrate squamous epithelial metaplasia and dysplasia of the endometrium, associated with HPV DNA of viruses typically of low oncogenic potential.