2026 Poster Presentations
P295: DELAYED LOCAL RECURRENCE IN HPV-RELATED MULTIPHENOTYPIC SINONASAL CARCINOMA
Jessica Eaton, MD; Danielle Dang; Katharine Price; Jaoquin Garcia; Janalee Stokken; Michael Link; Mayo Clinic
Introduction: It is well known that human papillomavirus is implicated in about 25% of head and neck carcinomas, including those found in the sinonasal tract. HPV-associated malignancy is classically associated with non-keratinizing squamous cell carcinoma. In 2013, Bishop et al described an HPV-associated malignancy that was morphologically similar to adenoid cystic carcinoma, designated “HPV-related carcinoma with adenoid-cystic like features”. In 2017, a larger case series expanded on this diagnosis, finding that the range of histological findings was actually much broader than originally thought. Now designated HPV-related multiphenotypic sinonasal carcinoma (HMSC), this malignancy of the sinonasal tract that is associated with human papillomavirus (HPV) but also has features of salivary gland carcinomas such as adenoid cystic carcinoma as well as squamous cell carcinoma-type features. We present a case of a recurrent tumor that was originally diagnosed in 2017 as HPV-related carcinoma with adenoid cystic-like features, now known to be HPV-related multiphenotypic sinonasal carcinoma. We review the unusual histologic features and clinical course of the patient, who had a delayed locla recurrence.
Illustrative Case: A 60-year-old male with a history of basal cell carcinoma of the forehead, a 60-pack year smoking history and a long history of working in a paper mill presented to an outside hospital with epistaxis and congestion in 2017. He underwent endoscopic sinus surgery and resection of a nasal septal mass. Pathology was consistent with invasive poorly differentiated carcinoma with basaloid features and adenoid cystic-like features with HPV E6/E7 positivity. He was taken to the operating room at our institution for a repeat margin analysis and clearance with medial maxillectomy and sphenoid drill-out. A muti-disciplinary tumor board recommended against adjuvant therapy at that time. In July of 2025, he re-presented with 6 weeks of left nare drainage concerning for rhinorrhea and a recurrence of the left nasal septal mass. He underwent a combined bifrontal craniotomy and endoscopic endonasal approach with multi-layered reconstruction of the anterior skull base and negative margins were achieved both intracranially and intranasally. Final pathology was consistent with a grade 3 nonkeratinizing papillary squamous cell carcinoma. Post-operatively he underwent proton radiation therapy.
The pathology in 2017 described invasive poorly differentiated carcinoma with basaloid features, consistent with HPV-related carcinoma with adenoid cystic-like features. Immunoperoxidase studies were positive for Cam 5.2 and CD117, highlighting a focal ductal epithelial component, and in situ hybridization studies were positive for HPV. The pathology in 2025 was described as invasive poorly differentiated papillary squamous cell carcinoma, staining positive for p63 and p40, a basal/myoepithelial cell marker. The tumor also tested positive for HPV. While these could easily be mistaken for unrelated diagnoses, they are in fact both reflective of HPV-related multiphenotypic sinonasal carcinoma, a difficult diagnosis given its broad range of morphologic features that can occur across the tumor.
Given limited literature on this rarely reported tumor, it is important to note this local recurrence that occurred over 8 years from the original diagnosis, which has important implications for long-term follow-up.
