Sinonasal Squamous Cell Carcinoma: A Review with Emphasis on Emerging Histologic Subtypes and the Role of Human Papillomavirus.

The sinonasal tract is one of the least frequent sites for squamous cell carcinoma in the head and neck. However, it is still a complex tumor type for pathologists because there are numerous histologic variants with unusual morphologic features, several non-squamous carcinomas in the differential diagnosis that can have similar morphology and even squamous differentiation, and because of the increasing recognition of human papillomavirus (HPV) in a subset of the tumors. In addition, the unique and complex anatomy of the sinonasal tract can make proper staging and management of patients' tumors quite challenging. This article reviews sinonasal tract squamous cell carcinoma in depth and provides the latest data on Schneiderian papillomas and HPV in their pathogenesis.