Extensive HPV-related carcinoma in situ of the upper aerodigestive tract with 'nonkeratinizing' histologic features

Prevalence of High-Risk Human Papillomavirus in Tonsil Tissue in Healthy Adults and Colocalization in Biofilm of Tonsillar Crypts

IMPORTANCE

The pathogenesis of human papillomavirus (HPV)-associated oropharyngeal squamous cell carcinoma is currently an important topic of elucidation. The presence of latent HPV infection in tonsil tissue of healthy adults may provide an explanation for a component of this process and contribute to the understanding of HPV-associated squamous cell carcinoma oncogenesis of the oropharynx.

OBJECTIVE

To determine the prevalence of oropharyngeal HPV and to determine the spatial relationship between the virus and crypt biofilm in tonsil tissue.

DESIGN, SETTING, AND PARTICIPANTS

A retrospective, cross-sectional study was carried out using samples obtained from tonsils that were archived at a university hospital following elective nononcologic tonsillectomy from 2012 to 2015. Samples consisted of formalin-fixed paraffin embedded samples of tumor-free tonsil tissue from 102 adults between the ages of 20 and 39 years.

EXPOSURES

Human papillomavirus status was assessed by polymerase chain reaction, and high-risk subtypes 16 and 18 were assessed with quantitative polymerase chain reaction assay. Samples that demonstrated presence of HPV were then analyzed by in situ hybridization to localize the viral capsid protein. These samples were then stained with concanavalin A to establish biofilm presence and morphology. These samples were also stained with diamidino-phenylindole (DAPI) to visualize location of the virus in relation to cell nuclei. These data were then assembled for aggregate analysis to colocalize HPV in the biofilm of the tonsillar crypts.

MAIN OUTCOMES AND MEASURES

Outcome measurements were determined prior to data collection and include prevalence of high-risk HPV types 16 and 18 in tonsil tissue of otherwise healthy adults, as well as demonstration with immunohistochemistry of HPV in tonsillar crypt biofilm.

RESULTS

In 102 otherwise healthy adults (55 [53.9%] female; age range, 20-39 years), the overall prevalence of HPV in tonsils was 4.9% (n = 5); and high-risk type 16 or 18, 3.9% (n = 4). In this sample population, in situ hybridization colocalized HPV virus to the biofilm of the tonsillar crypts.

CONCLUSIONS AND RELEVANCE

Biofilm is present in the tonsillar crypts in a considerable proportion of tonsil tissues and may be reproducibly identified. Human papillomavirus is demonstrated to colocalize to the crypt biofilm. This has important implications with respect to the determination of HPV prevalence rates in the oropharynx. It may also play a role in the pathogenesis of HPV-related oropharyngeal carcinoma.

Update from the 4th Edition of the World Health Organization Classification of Head and Neck Tumours: What is New in the 2017 WHO Blue Book for Tumours of the Hypopharynx, Larynx, Trachea and Parapharyngeal Space

Chapter 3 "Tumours of the hypopharynx, larynx, trachea, and parapharyngeal space" of the World Health Organization (WHO) Blue Book 2017 "Classification of Head and Neck Tumours" shows a shortened list of entities, especially due to reducing the number of benign and malignant soft tissue tumours, malignant melanoma and some others, which are transferred to more frequently affected regions of the head and neck. The basic concept of the new edition is to assimilate all advances concerning the discussed tumours in a shorter framework, appropriate for daily work. The main emphasis is on the most frequent lesions and tumors originating from the covering squamous epithelium. Laryngeal and hypopharyngeal conventional squamous cell carcinoma (CSCC), its variants and precursor lesions, occupy a major part of the chapter. New data on etiopathogenesis, with the focus on human papillomavirus (HPV) infection, are discussed in relation to the entities of the squamous epithelium. Although only a small fraction of these lesions are HPV-related, further studies are required for evaluation of the potential prognostic and therapeutic benefit of mRNA HPV determination. In contrast to earlier data, laryngeal and hypopharyngeal verrucous SCC, spindle cell SCC and basaloid SCC are not anymore considered as HPV-related tumours. New data on the pathogenesis of spindle cell SCC exhibiting divergent differentiation by epithelial-mesenchymal transition, are also briefly discussed. The most important innovation is brought by the section on precursor lesions, in which a unified two-tier classification, consisting of low- and high-grade dysplasia, is introduced. The proposed two-tier system can also be transformed into a three-tier classification for treatment purposes, with a distinction between carcinoma in situ and high-grade dysplasia. The reviewed morphological criteria of the proposed system are based on the amended Ljubljana classification. The section on laryngeal neuroendocrine carcinomas (NEC) represents a considerable improvement in terminology and classification. NEC are divided into well-, moderate- and poorly-differentiated neuroendocrine carcinoma. The latter is additionally divided into small cell NEC and large cell NEC (LCNEC). It is of extreme importance that LCNEC, which was associated in the WHO 2005 edition with atypical carcinoid/moderately differentiated neuroendocrine carcinoma, grade II, has now been transferred into the group of poorly differentiated NEC, grade III, displaying a specific morphology and poorer prognosis.

Squamous cell carcinoma of the upper aerodigestive tract: dysplasia and select variants

Upper aerodigestive tract (UADT) mucosal premalignant lesions include non-keratinizing and keratinizing intraepithelial dysplasia. The keratinizing type of intraepithelial dysplasia represents the majority of UADT dysplasias. Historically, grading of UADT dysplasias has followed a three tier system to include mild, moderate and severe dysplasia. Recent recommendations have introduced a two tier grading scheme to including low-grade (ie, mild dysplasia) and high-grade (moderate and severe dysplasia/carcinoma in situ) providing for better consensus among pathologists in the interpretation of such dysplastic lesions. Squamous cell carcinoma is the most common malignant neoplasm of the UADT. Several variants of squamous cell carcinoma are recognized among which the more common types include papillary squamous cell carcinoma, verrucous carcinoma, spindle cell squamous cell carcinoma (sarcomatoid carcinoma) and basaloid squamous cell carcinoma. Each of these variants of squamous cell carcinoma poses diagnostic challenges and each correlates to specific therapy and prognosis. This review details the proposed update in the grading of UADT dysplasia to a two-tiered system as well as providing the key diagnostic features for select variants of squamous cell carcinoma.

Nonkeratinizing Squamous Cell Carcinoma In Situ of the Upper Aerodigestive Tract: An HPV-Related Entity

The clinical and pathologic characteristics of human papillomavirus (HPV)-related premalignant lesions in the upper aerodigestive tract have not been adequately studied. There are a few reports of oral cavity HPV-related severe dysplasia with unique morphology (prominent apoptosis/karyorrhexis imparting a 'bowenoid' appearance) and a single case report of HPV-related squamous cell carcinoma in situ with nonkeratinizing histology distinct from the 'bowenoid' pattern that extensively involved the upper aerodigestive tract. The aim of this study was to characterize the morphologic and clinical features of HPV-related severe dysplasia/carcinoma in situ. All cases of upper aerodigestive tract severe dysplasia/carcinoma in situ (111 cases from 98 patients) at Washington University from July 2012 to March 2015 were categorized into histologic types: keratinizing, nonkeratinizing, mixed or 'bowenoid'. There were 83 (85 %) patients with keratinizing, 3 (3 %) nonkeratinizing and 12 (12 %) mixed patterns. The previously reported 'bowenoid' morphology was not identified. All 3 (100 %) nonkeratinizing and 6 (50 %) mixed cases were p16 and HPV RNA in situ hybridization (RNA ISH) positive (100 % concordance between p16 and RNA ISH). Only 2 of 73 keratinizing cases were p16 positive, 1 of which was also HPV RNA ISH positive (1.4 % of keratinizing cases HPV-related). Thus, nonkeratinizing morphology was a strong predictor of transcriptionally-active HPV in severe dysplasia/carcinoma in situ. HPV-related cases most commonly occurred in the floor of mouth and were frequently extensive (≥4 cm) or unresectable.

p16 expression independent of human papillomavirus is associated with lower stage and longer disease-free survival in oral cavity squamous cell carcinoma

There is limited information regarding the incidence of p16 expression, its association with human papillomavirus (HPV) and prognosis in oral cavity squamous cell carcinoma (OSCC). The role of p16 in OSCC is evaluated in 215 cases using tissue microarrays (TMAs). p16 immunohistochemistry and HPV in situ hybridisation were performed on TMAs following histopathology review of 215 patients with OSCC in the Sydney Head and Neck Cancer Institute database. Thirty-seven (17.2%) cases showed p16 expression without association with HPV. p16 expression significantly decreased with increasing pT category (p=0.002). p16 expression was associated with longer disease-specific survival on univariable analysis (p=0.044) but not on multivariable analysis adjusting for depth of invasion. Amongst patients receiving adjuvant radiotherapy, patients with p16 expression had significantly longer disease-free and overall survival. p16 expression was seen in early stage OSCCs and was associated with better survival following surgery and radiotherapy. While not an independent predictor of survival, p16 may mediate its effects by contributing to reduced proliferative capacity, leading to smaller tumour size and lower invasive potential.

The potential impact of prophylactic human papillomavirus vaccination on oropharyngeal cancer

The incidence of oropharyngeal cancer (OPC) is significantly increasing in the United States. Given that these epidemiologic trends are driven by human papillomavirus (HPV), the potential impact of prophylactic HPV vaccines on the prevention of OPC is of interest. The primary evidence supporting the approval of current prophylactic HPV vaccines is from large phase 3 clinical trials focused on the prevention of genital disease (cervical and anal cancer, as well as genital warts). These trials reported vaccine efficacy rates of 89% to 98% for the prevention of both premalignant lesions and persistent genital infections. However, these trials were designed before the etiologic relationship between HPV and OPC was established. There are differences in the epidemiology of oral and genital HPV infection, such as differences in age and sex distributions, which suggest that the vaccine efficacy observed in genital cancers may not be directly translatable to the cancers of the oropharynx. Evaluation of vaccine efficacy is challenging in the oropharynx because no premalignant lesion analogous to cervical intraepithelial neoplasia in cervical cancer has yet been identified. To truly investigate the efficacy of these vaccines in the oropharynx, additional clinical trials with feasible endpoints are needed. Cancer 2016;122:2313-2323. © 2016 American Cancer Society.

Laryngeal Squamous Intraepithelial Lesions: An Updated Review on Etiology, Classification, Molecular Changes, and Treatment

Laryngeal carcinogenesis is a multistep process, characterized by an accumulation of genetic changes associated with architectural and cytologic alterations, ranging from squamous hyperplasia to carcinoma in situ and encompassed by the terminology of squamous intraepithelial lesions (SILs). The etiology, classification, genetic changes, and malignant progression of these lesions are reviewed. Tobacco remains the principal etiological factor with gastroesophageal reflux disease recently considered as a possible factor. In contrast, there is little evidence that microbiological agents, especially human papillomavirus infection, are frequently involved in laryngeal carcinogenesis and probably <10% of SILs are driven by biologically active human papillomavirus infection. Light microscopy, despite a degree of subjectivity, remains the mainstay of accurate diagnosis, prognosis, and guidance for a patient's treatment. The currently used classifications, the dysplasia system, squamous intraepithelial neoplasia, and the Ljubljana classification, reflect different standpoints on this important topic. The modified Ljubljana classification, with good interobserver agreement, could be considered as a proposal for a unified classification of laryngeal SILs. This review also briefly discusses recently discovered genetic changes, such as CDKN2A and CTNNB1 genes, and chromosome instability of chromosomes 1 and 7; however, none of these can at present improve histologic diagnosis. Malignant progression of precursor lesions varies from 2% to 74%, according to different studies. Cold-steel microinstruments, CO2 laser, and radiotherapy are used to treat the different grades of precursor lesions. There is as yet no worldwide agreement on the treatment of high-grade lesions and carcinoma in situ.

Current views and perspectives on classification of squamous intraepithelial lesions of the head and neck

The current state in the field of classifying oral and laryngeal precursor lesions, as proposed in the WHO 2005 Blue Book is not ideal. The results of various inter-observer studies have shown that the currently used grading systems, with different basic concepts and different terminology, cannot continue to be reliably used in the future. The different etiology of cervical and head and neck precursor lesions requires a classification designed to cater to the specificities of the head and neck region. Trying to harmonize different classifications of the oral and laryngeal precursor lesions, we have proposed four crucial steps to set up a unified classification of squamous intraepithelial lesions (SILs): (a) the classification should contain two grades, low-grade and high-grade lesions and, specifically for the larynx, an additional grade-carcinoma in situ (CIS) which must be separated from high-grade laryngeal SILs; (b) the terminology should be unified; our preference is for the term SIL over squamous intraepithelial neoplasia; (c) all leading morphological criteria for low- and high-grade lesions, as well as for CIS, should be clearly defined; (d) agreement between clinicians and pathologists should be achieved on the most appropriate choice of treatment of different grades of SILs in separate head and neck areas.