Human Papillomavirus (HPV)-Related Carcinoma of the Oropharynx with Squamous Cell and Adenoid Cystic Carcinoma-Like Features: Report of a Case

Diagnostic algorithm for challenging blue cell sinonasal carcinoma

The newly emerging sinonasal carcinomas have demonstrated diverse morphologies and specific molecular rearrangements along with deviant clinical behavior from conventional counterparts. We aim to propose a diagnostic algorithm that is based on molecular findings of each sinonasal cancer and is considering the new entities has been called upon. Such a diagnostic algorithm should help diagnostic pathologists establish a diagnosis of a challenging sinonasal blue cell carcinomas and researchers performing retrospective analysis of archival cases. Along with consulting our archival cases, literature mining was conducted to retrieve the immunohistochemical and molecular findings regarding the newly emerging entities. Our proposed algorithm distinguishes poorly differentiated (non) keratinizing SNSCC, from anaplastic myoepithelial carcinoma, NUT midline carcinoma, SMARCB1/SMARCA4-deficient teratocarcinosarcoma, SMARCB1/SMARCA4-deficient carcinosarcoma, olfactory neuroblastoma, sinonasal undifferentiated carcinoma, HPV-related multiphenotypic sinonasal carcinoma and other adenocarcinomas. By incorporating morphologic features, immunohistochemical markers, and molecular investigations, the algorithm enhances the accuracy of diagnosis, particularly in cases where comprehensive molecular testing is not readily available. This algorithm serves as a valuable resource for pathologists, facilitating the proper diagnosis of sinonasal malignancies and guiding appropriate patient management.

Analysis of Human Papillomavirus (HPV) and Polyomaviruses (HPyVs) in Adenoid Cystic Carcinoma (AdCC) of the Head and Neck Region Reveals Three HPV-Positive Cases with Adenoid Cystic-like Features

An aetiological role of human papillomavirus (HPV) and/or human polyomaviruses (HPyVs) has been proposed in adenoid cystic carcinoma (AdCC). Moreover, HPV-related multiphenotypic carcinoma (HMSC) was recently introduced as an emerging entity of the sinonasal region. Here, we primarily want to study the role of HPV/HPyV in a large AdCC cohort and, secondly, possibly identify and characterize HMSC. Tumour DNA from 68 patients initially diagnosed with AdCC between 2000 and 2012 was, therefore, tested for 27 HPV types and 10 HPyVs. HPV DNA-positive samples were micromorphologically re-evaluated, further stained for p16^INK4a, S100, p63 and CD117 and tested for the presence of the MYB-NFIB fusion transcript. Notably, no samples were HPyV-positive, while one sinonasal and two tonsillar carcinomas were HPV- and p16-positive. After re-evaluating the micromorphology, immunohistochemistry and presence of fusion transcripts, all tumours had the same appearance and fitted within the diagnosis of HMSC, but in all these three cases, the morphology of the HMSC and basaloid squamous cell carcinoma was overlapping. We conclude that HPV and HPyV have no major role in AdCC. However, based on our data, we also suggest that HMSC should be considered as a basaloid variant of squamous cell carcinoma, and not its own entity, until better characterized.

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.