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Endoscopy Classification Cheat Sheet
The essential classification systems every endoscopist needs, organized in one searchable reference. Built for rapid retrieval before your next case.
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Esophagus
Stomach
Colon
Biliary / Pancreas
General
Showing 12 classifications
Paris Classification
Superficial GI Neoplastic Lesion Morphology
| Type | Subtype | Description |
|---|---|---|
| 0-Ip | Polypoid | Pedunculated (with stalk) |
| 0-Isp | Polypoid | Semi-pedunculated (short stalk) |
| 0-Is | Polypoid | Sessile (broad-based, no stalk) |
| 0-IIa | Non-polypoid | Slightly elevated (< 2.5 mm above mucosa) |
| 0-IIb | Non-polypoid | Completely flat |
| 0-IIc | Non-polypoid | Slightly depressed |
| 0-III | Excavated | Ulcerated / excavated lesion |
Clinical Pearl: Combined morphologies are common (e.g., IIa+IIc). The depressed component (IIc) is the strongest predictor of submucosal invasion, regardless of size. Always report the dominant morphology first.
Kudo Pit Pattern Classification
Colorectal Polyp Surface Pattern Analysis
| Type | Pattern | Histology | Management |
|---|---|---|---|
| I | Round (normal) | Normal mucosa | No resection |
| II | Stellar / papillary | Hyperplastic | No resection (generally) |
| IIIS | Small round / tubular | Adenoma (tubular) | Endoscopic resection |
| IIIL | Large round / tubular | Adenoma (tubulovillous) | Endoscopic resection |
| IV | Dendritic / gyrus-like | Adenoma (villous) | Endoscopic resection |
| V-I | Irregular / distorted | Carcinoma (SM superficial) | EMR/ESD possible |
| V-N | Non-structural | Carcinoma (SM deep invasion) | Surgery |
Clinical Pearl: Kudo V-N (non-structural, amorphous pattern) is the strongest endoscopic predictor of deep submucosal invasion and mandates surgical referral. Types I and II are generally non-neoplastic and can be left in situ.
JNET Classification
NBI Magnification for Colorectal Lesions
| Type | Vessel Pattern | Surface Pattern | Likely Histology |
|---|---|---|---|
| Type 1 | Invisible or faint | Regular dark/white spots of uniform size | Hyperplastic / SSP |
| Type 2A | Regular caliber, meshed/spiral | Regular (tubular/branched/papillary) | Low-grade dysplasia adenoma |
| Type 2B | Irregular caliber, non-uniform | Irregular or obscure | High-grade dysplasia / SM-superficial Ca |
| Type 3 | Loose vessel areas, interruption | Amorphous or absent | Deep SM invasive carcinoma |
Clinical Pearl: JNET 2B is the “gray zone.” These lesions require careful assessment with magnification. Some are amenable to ESD, but many harbor deep submucosal invasion. When in doubt, prioritize marking and multidisciplinary discussion over immediate resection.
Prague C & M Criteria
Barrett’s Esophagus Segment Measurement
| Component | Measurement | Description |
|---|---|---|
| C (Circumferential) | cm from GEJ | Length of circumferential columnar-lined esophagus above the GEJ |
| M (Maximum) | cm from GEJ | Maximum extent (including tongues) of columnar epithelium above GEJ |
Reporting format: CxMy (e.g., C3M5 = 3 cm circumferential, 5 cm maximum extent). Islands of columnar mucosa above the M extent should be reported separately.
Clinical Pearl: The GEJ is defined by the proximal margin of the gastric folds, NOT the Z-line. Short-segment Barrett’s (< 3 cm) has poorer inter-observer agreement. Always document landmarks carefully and use the Seattle biopsy protocol (4-quadrant biopsies every 1-2 cm).
Los Angeles Classification
Reflux Esophagitis Grading
| Grade | Mucosal Break Description |
|---|---|
| Grade A | One or more mucosal breaks, each no longer than 5 mm, not extending between tops of mucosal folds |
| Grade B | One or more mucosal breaks > 5 mm, not extending between tops of two mucosal folds |
| Grade C | Mucosal breaks extending between tops of two or more mucosal folds, involving < 75% of circumference |
| Grade D | Mucosal breaks involving >= 75% of the esophageal circumference |
Clinical Pearl: LA Grade A has poor inter-observer agreement and may represent a normal finding. Grades C and D are definitively pathologic and strongly predict abnormal acid exposure on pH testing. Always assess after at least 2 weeks off PPI when grading for diagnostic purposes.
Zargar Classification
Caustic Injury / Corrosive Ingestion Grading
| Grade | Endoscopic Findings | Prognosis |
|---|---|---|
| 0 | Normal mucosa | Excellent |
| 1 | Edema, hyperemia of mucosa | Excellent, no stricture |
| 2a | Superficial ulcers, erosions, friability, blisters, exudates, hemorrhage | Good, rare stricture |
| 2b | Deep discrete or circumferential ulcers | Stricture possible |
| 3a | Small, scattered areas of necrosis | Stricture likely |
| 3b | Extensive necrosis | High mortality risk, perforation |
Clinical Pearl: Endoscopy should be performed within 12-48 hours of ingestion. Grade 3b injuries carry significant mortality risk and may require surgical consultation. Do NOT advance past areas of significant necrosis. Nasogastric tube placement under direct vision is appropriate for Grade 2b+ injuries.
Updated Sydney Protocol
Standardized Gastric Biopsy Sampling
| Site | Location | # Biopsies |
|---|---|---|
| A1 | Lesser curvature of the antrum (2-3 cm from pylorus) | 1 |
| A2 | Greater curvature of the antrum (2-3 cm from pylorus) | 1 |
| IA | Incisura angularis (lesser curvature) | 1 |
| B1 | Lesser curvature of the corpus (approximately 4 cm from cardia) | 1 |
| B2 | Greater curvature of the corpus (middle of body, approximately 8 cm from cardia) | 1 |
Total: 5 biopsies minimum, submitted in separately labeled containers. Additional biopsies from any visible lesion should be submitted separately.
Clinical Pearl: The incisura angularis biopsy is the most sensitive single site for detecting intestinal metaplasia and early atrophic gastritis. Do not skip it. Separate containers are critical: antrum and corpus pathology can differ significantly and influence H. pylori treatment decisions.
Bismuth-Corlette Classification
Hilar Bile Duct Strictures / Cholangiocarcinoma
| Type | Description | Resectability |
|---|---|---|
| Type I | Below the confluence of the left and right hepatic ducts | Resectable |
| Type II | Reaches the confluence but does not involve left or right hepatic ducts | Resectable |
| Type IIIa | Involves the right hepatic duct (extending to the right secondary confluence) | Potentially resectable |
| Type IIIb | Involves the left hepatic duct (extending to the left secondary confluence) | Potentially resectable |
| Type IV | Involves both right and left hepatic ducts (multicentric or bilateral extension) | Usually unresectable |
Clinical Pearl: In suspected Klatskin tumors, avoid stenting both ducts at ERCP before surgical consultation. Unilateral stenting of the future liver remnant is preferred. Contrast injection into a duct you cannot drain dramatically increases cholangitis risk. MRCP should precede ERCP for staging.
Stapfer Classification
ERCP-Related Duodenal Perforations
| Type | Mechanism | Location | Management |
|---|---|---|---|
| Type I | Lateral or medial duodenal wall perforation (by scope) | Periampullary / duodenal | Usually surgical |
| Type II | Periampullary (sphincterotomy-related) | Perivaterian | Usually conservative (clips, stent, NPO, antibiotics) |
| Type III | Distal bile duct perforation (by guidewire or basket) | CBD / intrahepatic | Conservative (bile duct stent) |
| Type IV | Retroperitoneal air only (no visible perforation) | Retroperitoneum | Conservative (observation) |
Clinical Pearl: Type I perforations are the most dangerous and often require immediate surgical repair. Type II perforations (sphincterotomy-related) can frequently be managed endoscopically with clips and/or a fully covered metal stent across the defect, combined with NPO status and broad-spectrum antibiotics. CT abdomen is essential for staging.
Classification of Hiatal Hernias
Types I-IV by GEJ and Fundus Position
| Type | Name | Anatomy |
|---|---|---|
| Type I | Sliding | GEJ migrates above diaphragm. Most common (95%). Fundus remains below. |
| Type II | Paraesophageal (true) | GEJ remains in normal position. Fundus herniates through hiatus alongside esophagus. |
| Type III | Mixed | Combination of Type I and II. Both GEJ and fundus migrate above diaphragm. |
| Type IV | Complex paraesophageal | Large defect with herniation of other organs (colon, spleen, omentum) into thorax. |
Clinical Pearl: Types II-IV (paraesophageal) carry a risk of incarceration/volvulus and merit surgical evaluation. Cameron lesions (linear gastric erosions at the diaphragmatic hiatus) are a common cause of occult iron-deficiency anemia in large hernias and are easily missed if not specifically sought.
WHO Serrated Polyp Classification
Serrated Lesion Subtypes and Malignant Potential
| Subtype | Key Features | Location | Malignant Potential |
|---|---|---|---|
| Hyperplastic Polyp (HP) | Small (<5 mm), pale, no dysplasia | Predominantly left colon / rectum | Negligible |
| Sessile Serrated Lesion (SSL) | Flat, mucus cap, irregular borders, boot-shaped crypts | Predominantly right colon | Significant (via BRAF / CpG island methylation) |
| SSL with Dysplasia | SSL features + cytological dysplasia | Right colon | High (accelerated progression) |
| Traditional Serrated Adenoma (TSA) | Protuberant, villiform, eosinophilic cells, ectopic crypt formation | Left colon / rectum | Moderate (via KRAS or BRAF) |
Clinical Pearl: SSLs are the most clinically important serrated lesions and the most frequently missed. They appear as flat, pale lesions with a mucus cap and indistinct borders, often in the right colon. NBI can paradoxically make them harder to see. White light with adequate insufflation and careful washing is key.
Forrest Classification
Peptic Ulcer Bleeding Stigmata
| Class | Description | Rebleeding Risk | Endoscopic Rx? |
|---|---|---|---|
| Ia | Spurting hemorrhage | ~90% | Yes (mandatory) |
| Ib | Oozing hemorrhage | ~50% | Yes (mandatory) |
| IIa | Non-bleeding visible vessel (NBVV) | ~40-50% | Yes (recommended) |
| IIb | Adherent clot (non-removable) | ~25-30% | Consider (remove clot, treat if SRH) |
| IIc | Flat pigmented spot | ~7-10% | No (PPI only) |
| III | Clean-base ulcer | ~3-5% | No (PPI only) |
Clinical Pearl: For Forrest IIb (adherent clot), current guidelines recommend vigorous irrigation to dislodge the clot and treat the underlying stigmata. Dual endoscopic therapy (epinephrine injection + mechanical/thermal) remains standard of care for Forrest Ia-IIa. Clean-base ulcers (III) can be fed and discharged early.