Non-squamous variants of human papillomavirus-related head and neck carcinoma

Human papillomavirus (HPV) is now well established as an important causative agent in a subset of head and neck cancers. HPV-related head and neck carcinomas are important to recognize because these malignancies are associated with better survival and an improved response to therapy when compared to their HPV-negative counterparts. HPV-related head and neck cancer characteristically takes the form of a non-keratinizing squamous cell carcinoma. Widespread HPV testing of head and neck tumours, however, has revealed variants that depart from the standard HPV-related squamous cell carcinoma morphology. Most recently, examples of HPV-related carcinomas that actually lack a squamous phenotype, at least partially, have been reported. This manuscript will discuss these non-squamous variants of HPV-related head and neck carcinomas: adenosquamous carcinoma, adenocarcinoma, small cell carcinoma, sarcomatoid carcinoma, and sinonasal carcinoma with adenoid cystic-like features.