Case ReviewsUnusual Human Papillomavirus–Related Neoplasms of the Head and Neck A Case Series and Review of LiteratureDevins, Kyle M. MD; Baloch, Zubair MD; LiVolsi, Virginia MDAuthor Information From the Department of Pathology and Laboratory Medicine, Hospital of the University of Pennsylvania, Philadelphia, PA. Reprints: Kyle M. Devins, MD, Founders Pavillion, Hospital of the University of Pennsylvania, 3400 Spruce St, Philadelphia, PA 19104. E-mail: firstname.lastname@example.org. The authors have no funding or conflicts to declare. AJSP: Reviews & Reports: January/February 2020 - Volume 25 - Issue 1 - p 3-7 doi: 10.1097/PCR.0000000000000353 Buy Metrics Abstract Oropharyngeal squamous cell carcinoma accounts for the majority of human papillomavirus (HPV)–related neoplasms in the head and neck. However, recent studies have identified high-risk HPV in other, clinicopathologically distinct tumors in this region. We report a series of cases involving two unique HPV-mediated neoplasms. Human papillomavirus–related multiphenotypic sinonasal carcinoma is a locally aggressive tumor arising exclusively in the sinonasal tract with pathologic features reminiscent of high-grade adenoid cystic carcinoma. Ciliated adenosquamous carcinoma often presents as a unilateral neck mass and consists of admixed nonkeratinizing squamous cell carcinoma and glandular elements, which may be deceptively bland. Cilia are often present, which are traditionally associated with benignity and may lead to misdiagnosis as a benign branchial cleft cyst. In most cases, an oropharyngeal primary tumor is later identified. Despite aggressive features, both entities have a relatively favorable prognosis. These unusual tumors present unique diagnostic challenges that require particular attention to prevent misdiagnosis and mistreatment. © 2020 Lippincott Williams & Wilkins, Inc.