Abstract
We present a rare case of primary subglottic schwannoma in a 51-year-old man. He presented with subacute dyspnea and progressively worsening stridor. Videoendoscopy revealed the presence of a submucosal mass in the subglottic area, which measured 2 cm in diameter and had occluded approximately 80% of the lumen. Computed tomography (CT) and magnetic resonance imaging (MRI) showed a tumor arising from the left posterior wall of the subglottis and extending from the level of the cricoid cartilage to the first tracheal ring. After tracheostomy for airway management, subglottic schwannoma was diagnosed via fiberscopy-assisted punch biopsy. We removed the tumor via a medial thyrotomy (laryngofissure), and the post-excisional raw surface of the cricoid and tracheal cartilage was covered with a free buccal mucosal flap, which was attached using absorbable sutures and fibrin glue. No complications including recurrent nerve palsy developed after the procedure, and early postoperative ambulation was successfully performed. The patient is currently well, and the subglottic wound is clear. Although long-term follow-up is required, medial thyrotomy and coverage of the exposed cartilage with a free buccal mucosal flap is more effective for large subglottic schwannomas than laryngeal or tracheal resection with permanent tracheal tunnel formation from the viewpoint of phonation disability and the risk of complications.
1
Introduction
Schwannoma is a benign encapsulated tumor that originates from Schwann cells, and about 25% to 45% of all schwannomas present in the head and neck region, most of which develop in the parapharyngeal space . However, schwannoma rarely occurs within the larynx. Since the first report in 1925, about 130 cases of laryngeal schwannoma have been reported in the literature . The vast majority of reported laryngeal schwannomas were supraglottic, e.g., they affected the arytenoid cartilage, aryepiglottic fold, or false vocal cords; hence, subglottic schwannomas are very rare. There are only two reports of subglottic schwannomas developing in pediatric patients , and there are no such reports in the Japanese literature. Airway obstruction caused by a growing subglottic tumor requires surgical resection. However, there is no agreement regarding the optimal method for removing such tumors. Endoscopic or direct laryngoscopic excision might be preferable for small tumors, since subglottic lesions require a transglottic approach, and the glottic chink is small. For large tumors in the subglottis, an external approach, particularly median thyrotomy (laryngofissure), is advocated because it exposes the subglottis and facilitates mucosal grafting of the exposed cartilage .
We describe the first case of subglottic schwannoma to be treated with tracheotomy followed by complete resection involving medial thyrotomy and the coverage of the exposed cartilage with a free buccal mucosal flap.
2
Case report
A 51-year-old Japanese male presented with a one-month history of hoarseness after initially suffering from hemoptysis and 2 weeks of progressively worsening dyspnea and stridor. He had never smoked and had not displayed any throat-related symptoms before the hoarseness developed. An examination performed with a flexible video endoscope revealed the presence of a submucosal bulging in the subglottic area, which measured 2 cm in diameter and had occluded approximately 80% of the lumen ( Fig. 1 ). His vocal cord movement was normal. Computed tomography (CT) demonstrated a round, homogeneously enhanced mass in the subglottic area, but no evidence of marked destruction of the cricoid or tracheal cartilage ( Fig. 2 ). Magnetic resonance imaging (MRI) demonstrated a submucosal tumor arising from the left posterior wall of the subglottis and extending from the level of the cricoid cartilage to the first tracheal ring. The mass appeared isointense on T1-weighted MRI, hyperintense on T2-weighted MRI, and was homogeneously enhanced after the injection of gadolinium ( Fig. 2 ). A benign submucosal tumor other than hemangioma was suspected from an imaging series and the early progression of his airway symptoms. However, the bulky nature of the mass implied that it was malignant. The patient had undergone a right orchiectomy for seminoma in 2006, and prophylactic radiation treatment had been administered to the bilateral lungs. His postoperative course had been uneventful and complications-free ever since, but metastasis of the seminoma to the subglottic area was also suspected.
After tracheostomy was carried out under local anesthesia for airway management, subglottic schwannoma was diagnosed after several videoendoscopy-assisted punch biopsies of the submucosal mass. We decided to approach the lesion through a medial thyrotomy with anterior cricotomy ( Fig. 3 ). The tumor was rooted in the posterior portion of the subglottis and involved the cricoid cartilage. We removed the tumor via the partial resectioning of the cricoid and first tracheal ring cartilage. The post-excisional raw surface of the cricoid and tracheal cartilage was covered with a free buccal mucosal flap, which was attached with absorbable sutures and fibrin glue. We repaired the anterior cricoid and thyroid framework with braid polyglactin sutures. Macroscopically, the resected tumor was found to be an encapsulated elastic mass measuring 2.2 × 2.0 × 2.4 cm in size. The histological evaluation confirmed the diagnosis of schwannoma. The patient exhibited an uneventful postoperative course.
