Prague Classification is straightforward in concept. Two measurements: circumferential extent (C) and maximum extent (M) of columnar-lined esophagus above the GE junction. Most endoscopists learned it during training and use it routinely.
Where it gets tricky is the anchor point. Your Prague measurement is only as good as your GE junction identification. And the landmark most of us default to, the top of the gastric folds, has a couple of failure modes worth knowing about.
When gastric folds mislead you
Barrett’s patients can develop pseudo-folds in the columnar-lined esophagus that look like true gastric folds. If you anchor to a pseudo-fold, the entire measurement shifts.
There’s also the insufflation problem. A little too much air and the gastric folds flatten out. What looked like a clear GE junction becomes ambiguous, and a small tongue of columnar epithelium gets dismissed as “irregular Z-line” rather than measured and reported.
The palisade veins as a more reliable anchor
The submucosal venous plexus of the esophagus, the palisade veins, is visible on endoscopy and exists only in the esophagus. Not in the stomach. If you see palisade veins with columnar epithelium sitting on top instead of squamous epithelium, you’re looking at Barrett’s. No ambiguity about whether a fold is gastric or pseudo-gastric.
The Kyoto Classification and Consensus formally proposed the palisade veins as an endoscopic landmark for defining the GE junction. If you do variceal banding or POEM, you’ve already seen these veins. They’re the same vessels that give rise to esophageal varices in portal hypertension, and they’re clearly visible in the submucosal tunnel during POEM. You just may not have been using them as a Barrett’s landmark.
One more thing worth noting. The Z-line is inherently irregular. The name comes from the German “Zickzack” (zigzag). So “irregular Z-line” as a standalone finding shouldn’t trigger alarm or unnecessary biopsies. What matters is whether true tongues of columnar epithelium extend above the point where esophagus transitions to stomach. And to make that call, you need a reliable GE junction landmark.
Above is a 5-minute video lesson walking through the full Prague measurement with real endoscopic footage, followed by a written step-by-step guide with key frames from the video.
This lesson is from the Barrett’s Esophagus course on EndoCollab. Future lessons cover dysplasia detection with NBI and acetic acid, resection decision-making, surveillance intervals, and ablation techniques. Members get each lesson as it drops.
