S A Rasmussen1, J S Lewis2, L Mirabello3, S Bass3,4, M Yeager3,4, M J Corsten5, M J Bullock6. 1. Division of Anatomical Pathology, Queen Elizabeth II Health Science Centre, and Department of Pathology, Dalhousie University, 7th floor, MacKenzie Building, 5788 University Ave, Halifax, NS, B3H 1V8, Canada. sean.rasmussen@nshealth.ca. 2. Departments of Otolaryngology - Head and Neck Surgery, Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA. 3. Division of Cancer Epidemiology and Genetics (DCEG), National Cancer Institute, National Institutes of Health, Rockville, MD, USA. 4. Cancer Genomics Research Laboratory, Leidos Biomedical Research, Inc, Frederick, MD, USA. 5. Division of Otolaryngology - Head & Neck Surgery, Queen Elizabeth II Health Sciences Center and Dalhousie University, Halifax, NS, Canada. 6. Division of Anatomical Pathology, Queen Elizabeth II Health Science Centre, and Department of Pathology, Dalhousie University, 7th floor, MacKenzie Building, 5788 University Ave, Halifax, NS, B3H 1V8, Canada.
Abstract
BACKGROUND: Oropharyngeal squamous cell carcinoma is frequently associated with high-risk HPV infection, which confers a good prognosis. Immunohistochemistry for p16 is used as a surrogate for HPV status, but discrepant results are occasionally seen. Here, we report a case with a unique pattern of partial loss of p16. METHODS: A 63 year old male presented with a base of tongue nonkeratinizing squamous cell carcinoma and a large metastatic neck mass. The primary lesion and multiple regions of the metastatic mass were assessed with p16 immunohistochemistry, RNA in situ hybridization for high-risk HPV, and HPV16 genome sequencing. RESULTS: The primary lesion was p16 negative, and the metastatic neck mass had large, confluent regions that were either strongly p16 positive or entirely p16 negative. All of these regions were positive for high-risk HPV with identical HPV16 genomes. CONCLUSION: This unusual case illustrates a potential diagnostic pitfall, and it raises important questions regarding molecular mechanisms and prognostic implications of p16 staining in oropharyngeal squamous cell carcinoma.
BACKGROUND: Oropharyngeal squamous cell carcinoma is frequently associated with high-risk HPV infection, which confers a good prognosis. Immunohistochemistry for p16 is used as a surrogate for HPV status, but discrepant results are occasionally seen. Here, we report a case with a unique pattern of partial loss of p16. METHODS: A 63 year old male presented with a base of tongue nonkeratinizing squamous cell carcinoma and a large metastatic neck mass. The primary lesion and multiple regions of the metastatic mass were assessed with p16 immunohistochemistry, RNA in situ hybridization for high-risk HPV, and HPV16 genome sequencing. RESULTS: The primary lesion was p16 negative, and the metastatic neck mass had large, confluent regions that were either strongly p16 positive or entirely p16 negative. All of these regions were positive for high-risk HPV with identical HPV16 genomes. CONCLUSION: This unusual case illustrates a potential diagnostic pitfall, and it raises important questions regarding molecular mechanisms and prognostic implications of p16 staining in oropharyngeal squamous cell carcinoma.
Authors: Justin R Shinn; Seth J Davis; Krystle A Lang-Kuhs; Sarah Rohde; Xiaowei Wang; Ping Liu; William D Dupont; Dale Plummer; Wade L Thorstad; Rebecca D Chernock; Mitra Mehrad; James S Lewis Journal: Am J Surg Pathol Date: 2021-07-01 Impact factor: 6.298