The incidence of benign primary tumors of the esophagus is low. Most are leiomyomas, and schwannomas are rare. We report a patient with schwannoma who was referred to us for evaluation of a mediastinal tumor. Detailed examination yielded a diagnosis of schwannoma arising from the esophageal submucosa and radical surgery was performed.

Most tumorous lesions of the esophagus are esophageal cancers. Benign primary tumors of the esophagus are uncommon, and account for approximately 2% of all esophageal tumors. More than 80% of benign esophageal tumors are leiomyomas, with Schwannomas being rare [1, 2]. Schwannoma of the esophagus more frequently develops in women than in men and these tumors are often located in the upper and mid esophagus in the mid mediastinum. A preoperative diagnosis of this condition is difficult, and the definitive diagnosis is often established after resection [3]. A schwannoma that developed in the posterior mediastinum was reported [4]. Furthermore, a patient with a malignant schwannoma has also been reported, but such cases are extremely rare [5].

Symptoms of this disease include dysphagia, dyspnea, and chest pain, and are likely to appear and worsen as the schwannoma increases in size [6]. Fluorodeoxyglucose positron emission tomography as well as CT and MRI are reportedly useful for the confirmation of mediastinal tumors [7]. However, diagnosing a schwannoma is difficult with only imaging studies. In our present case as well, the results from the biopsy obtained with esophagogastroendoscopy were necessary for establishing the diagnosis. Schwannoma is a submucosal tumor, and endoscopic ultrasonography-guided fine needle aspiration biopsy is reportedly useful for both diagnosis and management [8].

In general, histological features of schwannoma include spindle-shaped tumor cells arranged in a palisading pattern or with loose cellularity in a reticular array. Immunohistochemical stainings for S100 protein, αSMA, CD34 and CD117 are also useful [9].

Chemotherapy and radiation therapy are ineffective such that surgical excision including the capsule is indicated for symptomatic cases and also for those with possibly malignant schwannoma. The use of enucleation with video-assisted thoracoscopic surgery is becoming common for small tumors (≤2 cm) [3]. However, for large tumors (≥8 cm) with broad areas adjacent to the esophageal muscular layer, the mucosal defect becomes extensive, and esophagectomy and esophagogastrostomy are thus usually performed [10]. In our present case, the tumor was approximately 8 cm in diameter, and the defect of the adventitia and muscular layer was extensive after tumor excision. Thus, direct anastomosis was considered to carry an increased risk for complications including anastomotic leakage and esophageal stricture. Therefore, esophagectomy and esophagogastrostomy were performed. Her postoperative course was uneventful. She had neither postoperative stricture nor problems with eating and drinking. This favorable outcome confirmed the procedure to have been appropriate.

Here, we report a relatively rare case of schwannoma of the esophagus, initially identified as a large mediastinal tumor. The tumor was 80 mm in diameter and the post-resection defect of the adventitia and muscular layer was extensive. Esophagectomy and esophagogastrostomy were thus performed and good postoperative recovery was achieved.

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