Specific features of laryngeal carcinoma involving the anterior commissure and the subglottic region.

The anterior commissure may be a line or an area with the same vertical extension as the vocal cords anteriorly. If it is an area it may laterally be bounded by the "maculae flavae". The subglottic region includes the under surface of the vocal cords corresponding to the mucosa covering the conus elasticus and the mucosa inferiorly to the lower border of the cricoid cartilage. Serial sectioning has proved that the weak spot of the laryngeal framework is the anterior midline as far as early tumor invasion of cartilage and extension of tumor outside the larynx through the cricothyroid membrane is concerned. Despite many unfavorable anatomico-pathological points at this site, radiotherapy gives at least as good results as those reported with conservative (voice conservation) surgery. Primary subglottic carcinomas are rare. In a series of 110 serially sectioned laryngectomy specimens only four were classified as subglottic. These tumors possess specific characteristics: an extensive circumferential growth, cartilage invasion, and spread outside the larynx through the cricothyroid membrane, to trachea or to the hypopharynx. Twenty-four tumors were classified as glottic-subglottic. Three of these invaded the thyroid cartilage and seven spread outside the larynx through the cricothyroid membrane. Vocal cord fixation occurred in all four subglottic and in six of the glottic-subglottic tumors. The thyroarytenoid muscle was most freqeuntly invaded. Thyroid gland invasion did not occur in any of the subglottic tumors. A metastatic focus of tumor was observed in one lobe of the thyroid in the glottic-subglottic group. Two neck dissections were performed in the subglottic group and one of these contained a metastatic carcinoma. Eleven neck dissections were performed in the glottic-subglottic group and three contained metastatic tumor.