Fig. 2

A patient who was diagnosed as HGIN on biopsy and subsequently upgraded to ESCC after resection. a A reddish flat lesion is observed in the middle esophagus; b the lesion is demarcated brownish area under narrow band imaging; c unstained area is observed after 1% iodine spraying. d One biopsy is taken from unstained area and is diagnosed as HGIN; e magnifying endoscopy shows type B1 IPCL; f higher irregular type B1 IPCL is observed within the area correspond to area (white dotted lines) in panel e; g pink color sign is positive in the area correspond to area (white dotted lines) in panel e; h circumferential incision was made after marking the lesions and submucosal injection; i submucosal dissection; j the lesion was completely removed; k resected specimen after 1% iodine spraying; l pathological diagnosed as esophageal squamous cell carcinoma in situ coexists with HGIN and LGIN; m the histology of No.8 slides is shown in low-power view; and histology in high-power view correspond to box in panel m was shown in n carcinoma in situ; o HGIN; and p LGIN