Papillary squamous carcinoma: Will the real one please stand up?

Pathologists seeking clinicopathologic definition of papillary squamous cel l carcinoma may, at times, feel as if they have been given a pathologic sal magundi to digest. Why the definition of the carcinoma is so elusive is unc lear. Perhaps one way to address the problem is to relate what the papillar y squamous cell carcinoma is not. It is not the verrucous carcinoma nor is it the exophytic, conventional squamous cell carcinoma, which is usually br oad-based, well-to-moderately differentiated, most often keratinizing, and with an easily defined invasive (endophytic) component. To date, however, t he few reports dealing with papillary squamous cell carcinoma have muddied diagnostic waters by definitely not excluding these other forms of squamous cell carcinoma. Three different perceptions of papillary squamous cell carcinoma of the upp er aerodigestive tract are presented in the commentary. Not only are the de scriptions and depictions of the cytomorphology different among the three, so too are the biologic courses and responses to therapy. We believe the pa pillary squamous cell carcinoma is a separable and definable clinicopatholo gic entity. The reader is left to choose.