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Accurate identification of the microscopic risk factors of oral and oropharyngeal (OP) squamous cell carcinomas
(SCC) and their morphologic variants is of at most importance, as these generally determine treatment modalities,
prognosis and overall patient outcome. The great majority of oral and oropharyngeal squamous cell carcinomas
are microscopically described as kerartinizing squamous cell carcinoma (KSCC). They bear certain resemblance
to keratinizing stratified squamous epithelium. Tobacco habits and excessive consumption of alcoholic beverages
have been considered to be the main etiologic agents in these carcinomas. The tumors occurred in older patients
more commonly affected the oral tongue and floor of the mouth with well established morphologic risk factors
including tumor grade, pattern of invasion and perineural involvement.
Within the last 30 years however, the advent and expanding prevalence of high risk human papillomavirus (HPV)
as an important etiologic agent for head and neck squamous cell carcinoma, particularly in the OP, has resulted
in a significant change in the established morphologic criteria for risk assessment. The majority of HPV relate
carcinomas of the OP are nonkeratinizing squamous cell carcinoma (NKSCC). These tumors are found to be more
responsive to treatment with a favorable patient outcome and good prognosis. Consequently, alterations in treat
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ment protocols aimed at de-escalation are currently being evaluated. More recently, other morphologic variants
that are HPV positive are reported with increasing frequency in the OP and other head and neck sites. As a result,
several clinical and pathologic questions have emerged. Importantly, whether the virus is biologically active in
these tumors and involved in their pathogenesis, and second, what are the clinical implications with regard to
patient management and outcome in the HPV-related variants.
Examples of HPV-related squamous cell carcinoma variants that will be addressed here are: basaloid squamous
cell carcinoma (BSCC), undifferentiated carcinoma (UCa), papillary squamous carcinoma (PSCC) and small cell
carcinoma. Some studies have suggested favorable prognosis in some variants, analogous to that of the (NKSCC),
while others showed poorer outcome. So far the number of studies on this subject is limited and the number of
cases evaluated in each investigation is few. Because of that, it is prudent at this stage, not to alter management
protocols as a result of identification of HPV in these variants and to await additional information.
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