Human papillomavirus-associated adenocarcinoma of the base of the tongue.

Human papillomavirus (HPV) is a major cause of oropharyngeal squamous cell carcinoma with characteristic clinical and pathologic features relative to their non-HPV-associated counterparts. Here we describe 2 cases of HPV-associated adenocarcinoma of the oropharynx. Both cases arose at the base of the tongue, and neither had the histologic or immunohistochemical features of a primary salivary gland tumor or metastasis from another location. One patient had metastases to neck lymph nodes and the lungs and died of disease 37 months after diagnosis. Evidence for an HPV association consisted of strong diffuse expression of p16, polymerase chain reaction-based detection of HPV16 DNA sequences, and localization of HPV by in situ hybridization within tumor cells of both primary and metastatic lesions. These results further expand the spectrum of HPV-associated head and neck malignancy. This rare entity should be distinguished from primary salivary gland adenocarcinoma and may be a candidate for HPV-specific targeted therapies.