Hideki Tateno

Surgical treatment of laryngotracheal stenosis by a trough technique.

Many methods have been tried and reported in the treatment of laryngotracheal stenosis. Among them, a trough technique seems universal at present. To date, we have tried several methods of this technique, but each method had its own demerits. We used, as a cartilagenous framework, a homograft or tracheal ring cartilages for the last four cases of laryngotracheal stenosis. These tracheal ring cartilages were resected from relatively young patients with laryngeal carcinoma. Total laryngectomy was done just below the level of the fourth tracheal ring, then the fourth tracheal ring was resected and stored in 70% alcohol. The cartilage was used after it was made certain pathologically that there was no invasion of carcinoma at the third tracheal ring level. The operative procedure of this trough technique is as follows. In the first stage, a trough is created at the stenosed region and the trough is maintained by placing a Quick Set Silicone (Q.S.S.) stent mold over it. While waiting for scar formation of the tissues surrounding the trachea, the second stage reconstruction is performed four weeks after the first. The trough is closed with hinged skin flaps on both sides, and the reserved tracheal ring cartilages are sutured every 5 mm onto the outer surface of the hinged skin flaps to make a cartilagenous framework. The neck is closed with advanced neck skin flaps. A more ideal tracheal lumen is created by this technique. Our four patients are doing well two years or more after the operation.

Scintiscanning of mucoepidermoid tumor of the parotid gland.

99mTc-O4 and/or 67Ga-citrate scintigraphies were preoperatively applied to 13 cases of parotid mucoepidermoid tumor. The resected specimens were histopathologically subdivided into three types: well (6 cases), moderately (one case), and poorly differentiated (6 cases). As the other parotid neoplasms except adenolymphoma and oxyphilic adenoma, all poorly differentiated tumors showed focal defect image in 99mTc-O4 scintiscanning (4/4). They indicated a focal hot image in 67Ga-citrate scanning at a high rate (4/6). Otherwise, well differentiated tumors were scarcely pointed out in cold image and were usually indicated as a symmetrical image (5/6) in 99mTc-O4 scanning. None of them showed a focal hot image in 67Ga-citrate scanning, but two cases indicated diffuse increased uptake and another case showed a focal defect image. The clinical prognosis of mucoepidermoid tumors is extremely correlated to the degree of cell differentiation in our prospective study. For that reason, the therapeutic method should be carefully selected in the tumors suspected of low grade malignancy. Our study suggests that RI (99mTc-O4 and 67Ga-citrate) scintigraphy is helpful in evaluating the malignancy grade of mucoepidermoid tumors.

Characteristics of Epithelial Component of Parotid Adenolymphoma

Parotid adenolymphoma is composed of two histologic components, epithelial and lymphoid. Although some theories regarding the histogenesis of this tumor have long been disputed, there have been no definite conclusions. The purpose of this study was to clarify the origin of the epithelial components of this tumor using histochemical and immunopathological techniques, electron microscopy and a survey of HE-stained tumor sections. The results obtained indicated that the functions of the epithelial components were similar to those of the striated duct of the normal parotid gland, and morphological studies showed that the origin of the epithelial components may arise from parotid ductal inclusion in the lymphnodes in or around the parotid gland.