LAUSR

Adenoid cystic carcinoma of the esophagus is a rare tumor and difficult to detect early [1, 2]. Esophageal squamous cell carcinoma (ESCC) has a characteristic magnifying endoscopic appearance [3]. However, adenoid cystic carcinoma of the esophagus can have atypical endoscopic features. An 84-year-old man underwent esophagogastroduodenoscopy (EGD) owing to retrosternal discomfort. EGD showed a flat (0-IIb) and slightly reddish lesion of 15×20mm in the middle esophagus (▶Fig. 1 a). The lesion appeared as a brownish area on narrow-band imaging (NBI) endoscopy (▶Fig. 1b, c). Endoscopic ultrasound (EUS) revealed the lesion primarily involved the mucosal layer of the esophagus with a hypoechoic area (▶Fig. 1d). NBI magnification revealed that the intrapapillary capillary loop pattern appeared to be type B1 (▶Fig. 2, ▶Video 1) based on the magnifying endoscopic classification of the Japan Esophageal Society. But near the anal area of this 2×2-mm lesion, the loop pattern appeared irregular and of the fine reticular (R) type (▶Fig. 2b) (red arrow). The endoscopic diagnosis was ESCC and the depth was mainly T1a-EP or T1a-LPM. Biopsy pathology suggested a high grade intraepithelial neoplasia (HGIN). This patient was eligible for endoscopic therapy. Therefore, an en bloc resection was performed by endoscopic submucosal dissection (ESD) (▶Fig. 3 a–f). From the second to eighth tissue strips, hematoxylin and eosin (H&E) stain showed HGIN with focally invasive SCC in the lamina propria (▶Fig. 3g) (blue circle). In the sixth strip, there are epithelioid cells arranged in a cribriform, tubular and solid architecture, which have no relation to the surface squamous epithelium and are restricted to the lamina propria (▶Fig. 4 a–c). Immunohistochemical analysis showed that these abnormally arranged epithelioid cells were positive for P40, SOX-10 and E-Videos