Human papillomavirus-related multiphenotypic sinonasal carcinoma: A report of two patients and review of the literature.

Human papillomavirus (HPV)-related multiphenotypic sinonasal carcinoma (HMSC) is a recently described sinonasal tract tumor that is associated with high-risk HPV subtype infection. Despite histological features that are suggestive of a high-grade malignant tumor, the prognosis of HMSC is relatively good; however, the clinical features of this tumor are poorly understood. Here, we describe two patients with HMSC. The first was initially diagnosed with adenoid cystic carcinoma of the right nasal cavity; the tumor was extirpated via endoscopic endonasal surgery. Seventy-four months later, the tumor recurred in the right inferior turbinate and was diagnosed as HMSC after biopsy, whereupon it was resected en block via endoscopic endonasal surgery. No adjuvant therapy was administered during either episode; moreover, no recurrences have occurred during the 44 months since the second operation. The second patient was diagnosed with HMSC based on the biopsy of the tumor occupying the left nasal cavity. The tumor was completely resected under endoscopic endonasal surgery, and no adjuvant therapy was administered. There has been no recurrence for 15 months after the operation. Herein, we also review the clinical features of this tumor type based on 69 previously reported cases as well as our patients.