Figure 3.

Endoscopic submucosal tunnel dissection with a single triangle-tip knife. A: Lugol staining to delineate the lesion, occupying almost half of the esophageal lumen. The margin was marked by argon plasma coagulation; B, C: Anal and oral incision was performed successively with a triangle-tip (TT) knife. Water jet helped entry into the submucosal tunnel; D: Submucosal tunnel was created from the oral to anal side; E: Lateral resection with a TT knife from the oral to anal side until reaching the anal incision; F: Complete en bloc resection was achieved in 52 min; G: The specimen, around 55 mm × 35 mm in size, was retrieved. Histopathological examination revealed a microinvasive squamous carcinoma limited in the lamina propria mucosa, free of lateral and vertical margin.