Growth patterns of piriform sinus carcinomas.

Advances in functional surgery have encouraged many head and neck surgeons to treat piriform sinus carcinomas, whenever possible, by conservation surgery. An increased understanding of the histopathologic growth pattern and spread of piriform sinus carcionomas is needed to define criteria for appropriate application of voice preservation surgery. The purpose of this study was to analyze the patterns of tumor spread to laryngeal and parapharyngeal structures. A total of 42 specimens obtained by laryngopharyngectomy were subjected to a whole-organ section study. Carcinomas confined to the lateral wall tended to extend laterally beyond the thyroid ala and rarely infiltrated the intrinsic laryngeal muscles. As a result, conservation surgery could be possible in many cases, including T4 carcinomas. Carcinomas confined to the medial wall or occupying the whole piriform sinus tended to infiltrate laryngeal structures early, and hemilaryngeal fixation was observed in 61% of these cases; tumor spread to the contralateral side in 64%. The hemilarynx fixation was due to an invasion of intrinsic laryngeal muscles. An isolated perineural or cricoarytenoid joint involvement was never observed. For these tumors, conservation surgery would be inadequate in most cases, as they often present extensive laryngeal involvement with spread to the contralateral side.