[On the mechanism of hemilaryngeal fixation in pyriform sinus carcinoma and its clinical significance].

To approach the mechanism of hemilaryngeal fixation in pyriform sinus carcinoma (PSC), surgical specimens from total laryngectomy and partial hypopharyngectomy in 43 cases of pyriform sinus carcinoma were studied using organ subserial sections. Invasion of intralaryngeal muscles and the upper and outer aspects of arytenoid cartilage via paraglottic space was found to be the main cause of hemilaryngeal fixation in these cases. Presence of tumor on the medial wall of the pyriform sinus makes involvement of intralaryngeal structures easy, and thus is more frequently seen with hemilaryngeal fixation. Clinical T3 lesion of the sinus may infiltrate laryngeal cartilages and adjacent soft tissue to become pathologic T4 lesion. For PSC appearing hemilaryngeal fixation, total laryngectomy is safer to thoroughly remove cancer.