An unusual case of esophageal submucosal tumor

This 66-year-old male has been experiencing chest discomfort for the past 3 months and dysphagia for the last 2 weeks. Esophagogastroduodenoscopy revealed a subepithelial-like protruding, hemi-circumferential mass lesion in the upper esophagus, leading to partial lumen obstruction. Additionally, engorged and tortuous superficial vessels were observed (Figure 1). Endoscopic Ultrasound with 20 MHz Miniature Probes (Olympus UM-3R-3) demonstrated focal wall thickening involving the muscularis mucosa, submucosa, and muscularis propria (Figure 2). The primary differential diagnoses for the lesion included malignancies originating from the submucosal layer, such as submucosal esophageal squamous cell carcinoma and submucosal gland carcinoma. Other potential differentials were gastrointestinal stromal tumor, malignant leiomyosarcoma, or neuroendocrine tumor. What is the diagnosis? A bite-on-bite biopsy revealed poorly differentiated carcinoma composed of epithelial and myoepithelial cells, favoring adenoid cystic carcinoma (ACC). Computed tomography showed eccentric wall thickening at the thoracic inlet level of the esophagus. The patient underwent a thoracoscopy-assisted subtotal esophagectomy with lymph node dissection and esophageal reconstruction. Final pathology confirmed ACC invading the adventitia (pT3) without lymph node involvement. Immunohistochemical staining for both CD117 and p63 returned positive results, confirming the diagnosis of advanced ACC. Postoperatively, the patient received adjuvant radiotherapy. ACC commonly originates in the major salivary glands and respiratory tract but is extremely rare in the esophagus. It is classified as a type of submucosal neoplasm.1 The most prevalent appearance on endoscopic findings was protruded (58.6%), followed by ulcerative (24.1%), as the tumor is typically covered by normal mucosa in the early stages, with ulceration developing as the tumor progresses.2 The most common depth of invasion is deep submucosa, making preoperative endoscopic biopsy less diagnostic. Due to the rarity of esophageal ACC and limited literature, treatment guidelines are scarce. Radical excision is the primary treatment choice, while chemotherapy is typically not preferred due to poor response rates.3 Postoperative radiotherapy may improve progressive dysphagia. Overall, the prognosis for ACC of the esophagus is better than that of conventional squamous cell carcinoma. The authors declare no conflicts of interest. According to the institutional review board (IRB), there is no need for IRB approval for an image article in our hospital. A written informed consent was obtained before starting, and the authors followed the principles outlined in the WMA Declaration of Helsinki throughout the writing process.