HPV-Related Multi-Phenotypic Sinonasal Carcinoma with Aggressive Clinical Behavior; A Rare Case

Introduction/Objective Human Papilloma Virus (HPV)-related multiphenotypic sinonasal carcinoma, previously known as HPV-related sinonasal carcinoma with adenoid cystic carcinoma-like features, is a rare type of sinonasal carcinoma with both epithelial-derived and salivary gland-type morphologic features. It is associated with high-risk HPV, but lacks MYB gene rearrangements. Methods/Case Report We report a case of a 59-year-old male who presented with a rapidly growing sinonasal mass. On MRI, a left nasal cavity lesion was identified growing laterally along the frontal process of the maxilla, extending into the middle meatus and into the maxillary sinus. Patient underwent a complex left medial maxillectomy, spheno- ethmoidectomy, and sinusotomy. On gross evaluation, the left inferior turbinate and sidewall demonstrated a 4 cm unremarkable turbinate with attached friable soft tissue. Microscopic examination revealed sections of carcinoma with various architectural patterns comprised of foci with adenoid cystic carcinoma-like morphology, basaloid squamous cell carcinoma and adenocarcinoma. The tumor showed positive immunostaining for P40, but focal reactivity to S100 and rare scattered reactivity with CD117. INI-1 immunostain was retained in tumor cells. P16 immunostain was strong and diffuse and high-risk cocktail HPV RNA ISH was positive. However, MYB FISH testing was equivocal. Morphologic and immunophenotypic findings were consistent with HPV-related multiphenotypic sinonasal carcinoma. The tumor involved the olfactory nerve fibers requiring a skull base resection and showed extension into the dura mater. Results (if a Case Study enter NA) NA Conclusion HPV related multiphenotypic sinonasal carcinoma is a recently described entity that can pose significant diagnostic challenge. It typically has an indolent clinical course with potential for late recurrences. This case study highlights the potential aggressive nature of this type of sinonasal carcinoma, despite association with high-risk HPV, and use of ancillary testing in aiding diagnosis.

Human Papillomavirus-Related Multiphenotypic Sinonasal Carcinoma—An Even Broader Tumor Entity?

Human papillomavirus (HPV)-related multiphenotypic sinonasal carcinoma (HMSC) is a recently defined tumor subtype with apparent favorable clinical outcome despite aggressive histomorphology. However, in recent years, additional numbers of cases, with more variable features and at locations outside the sinonasal region, have complicated the definition of HMSC. Here, we have performed a systematic review of all cases described so far in order to accumulate more knowledge. We identified 127 articles published between 2013 and 2021, of which 21 presented unique cases. In total, 79 unique patient cases were identified and their clinical and micromorphological nature are herein summarized. In our opinion, better clinical follow-up data and a more detailed tumor characterization are preferably needed before HMSC can finally be justified as its own tumor entity.