Table 1. Outline of UMEC.
| UMEC1 | UMEC2 | UMEC3 | |||
| UMEC2A | UMEC2B | ||||
| Expected histology | Non-neoplastic lesion | Intramucosal neoplasia | Deep submucosal invasive cancer | ||
| Benign ~ low grade neoplasia | High-grade neoplasia ~ Intramucosal cancer (shallow submucosal cancer) | ||||
| Esophagus | |||||
| E-UMEC1 | E-UMEC2A | E-UMEC2B | E-UMEC3 | ||
| Endoscopic finding | IPCL | Normal IPCL (The caliber of the vessels is about 7–10 μm) | Abnormal microvessels without severe irregularity (The caliber of the vessels is about 7–10 μm) | Abnormal microvessels with severe irregularity or highly dilated abnormal vessels (The caliber of the vessels is around 20 μm) | Highly dilated vessels which calibers appear to be more than three times that of usual E-UMEC2B vessels (The caliber of the vessels is often > 60 μm) |
| AVA | – | – | AVA-small, middle (smaller than 3 mm) | AVA-large (3 mm or larger) | |
| Expected histology (invasion depth) | Normal epithelium | Inflammation and LGIN | HGIN and SCC (T1a-EP, T1a-LPM, T1a-MM, T1b-SM1) | invasive SCC (T1b-SM2 or deeper) | |
| Stomach | |||||
| S-UMEC 1/2A | S-UMEC 2B/3 | ||||
| Endoscopic finding | DL | Absent | Present | Present | |
| Vascular and surface | – | Regular | Irregular microvascular pattern and/or Irregular microsurface pattern | ||
| Expected histology | Non-cancer | Cancer | |||
| Colon | |||||
| C-UMEC1 | C-UMEC2A | C-UMEC2B | C-UMEC3 | ||
| Endoscopic findings | Vessel | Invisible | Regular caliber Regular distribution | Variable caliber Irregular distribution | Loose vessel areas Interruption of thick vessels |
| Surface | Regular dark White spots similar to surrounding normal mucosa | Regular (tubular/branched/papillary) | Irregular or obscure | Amorphous areas | |
| Expected histology | Hyperplastic polyp Sessile serrated lesion (SSL) | Adenoma Low-grade dysplasia | High-grade dysplasia/mucosal cancer Shallow SM invasive cancer | Deep SM invasive cancer | |
UMEC, Unified Magnifying Endoscopic Classification; IPCL, intrapapillary capillary loop; AVA, avascular area; LGIN, low-grade intramucosal neoplasia; EP, epithelium; LPM, lamina propria mucosa; MM, muscularis mucosa; SM, submucosa; HGIN, high-grade intramucosal neoplasia SCC, squamous cell carcinoma; DL, demarcation line.