Gastroscholar

A Phrygian cap is a congenital fold of the gallbladder fundus on the body. It is common, incidental, and not a polyp. It does not need surgery and does not explain biliary colic. If the same report also lists a polyp, that lesion is the other URL.

Original GastroScholar summary card for Phrygian cap gallbladder anatomy. Not an ultrasound still.
Original GastroScholar summary card. Not an ultrasound still. This page does not invent a folded fundus photograph.

Experienced teaching points

Clinical Pearls

  1. Folded fundus, not a mass. Real-time ultrasound usually proves it when the 'septum' opens with position or a second look.
  2. It is not an indication for cholecystectomy. Stones, sludge, and polyps are.
  3. Duplication and intrahepatic gallbladder are the congenital variants that change the operation. The cap does not.
  4. True polyp size rules: gallbladder polyps (this site's /phrygian-cap-gallbladder/ URL).

GI Endoscopy · 5 min read

Phrygian Cap: A Fundal Fold, Not a Polyp and Not a Symptom

The fundus folds on the body. Sonographers mistake it for a septum or a mass. It does not cause biliary colic by itself.

Clinical Bottom Line

Finding What to do
Phrygian cap Fundus folded on the body. Incidental. No follow-up, no cholecystectomy for the fold itself.
Why it gets called Looks like a septum, a fundal mass, or trapped sludge on a single still. Real-time scanning usually settles it.
Pain The cap does not cause colic. Look for stones, sludge, microlithiasis, or another source. Do not operate on a name.
Other congenital maps Duplication and intrahepatic or left-sided gallbladder change cholecystectomy. Mention them on the op note. They are not this fold.
Polyp on the same report Size and risk factors decide, not the cap. That algorithm is the polyp page.

Does a Phrygian cap cause symptoms?

No. That is the honest answer to this slug. The leftover body already said so and then wandered into agenesis and duplication. Keep the cap as a fold. Keep duplication as a surgical miss if you leave the second gallbladder behind. Do not merge the two into a congenital-anomaly lecture that ends with "high risk."

If the ultrasound is truly confusing, a second look, or rarely MRCP, beats an automatic cholecystectomy. If there are stones, the stones are the indication. If there is a 10 mm polyp, the polyp is the indication. The hat-shaped fundus is scenery.

Selected references

  1. Foley KG, et al. Management and follow-up of gallbladder polyps. Eur Radiol. 2022;32:3358-3368. Use this when the same study also reports a polyp.

Last reviewed September 20, 2026. Written for clinicians who received an ultrasound that mentions a Phrygian cap and are wondering whether the pain or the fold is the problem.

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Congenital Gallbladder Anomalies: The Phrygian Cap and Beyond (2026)

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