Use of tunnel endoscopy for diagnosis of obscure submucosal esophageal adenocarcinoma: A case report and review of the literature with emphasis on causes of esophageal stenosis

Figure 4 Case illustration of endoscopic biopsy through a tunnel. A: The narrow place in the lower esophagus (37 cm from the incisors); B: The submucosal tunnel was established; C: White fibrotic adhesions can be seen in the tunnel; D: The submucous structure was disorganized; E and F: It was difficult to distinguish yellow tissue and white tissue from the muscular layer in the tunnel; G: Tissue biopsy in the tunnel; H: The mucosal entry incision was sealed with several clips.