[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [General pathology](https://durgical.com/en/general-pathology/) › [Liver and gallbladder](https://durgical.com/en/general-pathology/areas/liver/) › Congenital anomalies of the gallbladder

# Congenital anomalies of the gallbladder

- Lesion

The gallbladder can be folded, doubled, missing or in the wrong place; most of these cause no trouble.

Updated Nov 12, 2026

## Key points

- Phrygian cap: folding of the fundus, the most common anomaly; harmless.
- Agenesis of the gallbladder is rare; bile still drains through the ducts.
- Duplication or septation may cause stasis and stones.
- A floating gallbladder on a long mesentery is prone to torsion.
- Anomalies of the cystic duct and arteries matter in cholecystectomy.

## What it is

Congenital anomalies of the gallbladder come from errors in the budding of the hepatic diverticulum. The most common is the Phrygian cap, a folded fundus. Less common are agenesis, duplication, bilobed gallbladder, septation and ectopic positions (intrahepatic, left-sided, floating). Most are incidental, but some favour stasis and stones, or confuse imaging and surgery.

## Step by step

- In the fourth week, the hepatic diverticulum of the foregut gives off a caudal bud that forms gallbladder and cystic duct.
- Failure of the bud causes agenesis; splitting causes duplication or a bilobed organ.
- Incomplete vacuolization leaves septa.
- Abnormal position of the bud gives ectopic gallbladders.

## Congenital anomalies of the gallbladder

| Anomaly | What it is | Relevance |
| --- | --- | --- |
| Phrygian cap | Fundus folded over the body | Incidental, can mimic a mass on imaging |
| Agenesis | No gallbladder | Rare; may be missed as 'contracted' gallbladder |
| Duplication or bilobed | Two gallbladders or two lobes with one or two cystic ducts | Stasis, stones, surgical surprises |
| Septation | Internal septa | Stasis and stones |
| Ectopia | Intrahepatic, left-sided or on a long mesentery | Floating gallbladder may twist (torsion) |

## Memory aid

A cap, a twin, a missing one and a wanderer: the four ways the gallbladder can be born unusual.

## Test yourself

Think of the answer, then tap the question to see it.

## What is the most common congenital anomaly of the gallbladder?

The Phrygian cap, a folding of the fundus.

## Which gallbladder anomaly predisposes to torsion?

A floating gallbladder suspended on a long mesentery.

## Why can duplication of the gallbladder matter clinically?

It can cause bile stasis and stones and complicate cholecystectomy if not recognized.

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## Elsewhere in DurgiPedia

- [Liver, gallbladder and pancreas](https://durgical.com/en/embryology/liver-gallbladder-and-pancreas/)
- [Gallbladder and bile ducts](https://durgical.com/en/histology/gallbladder-and-bile-ducts/)

## Connections

## Related 2

- [Gallstones: cholesterol vs pigment](https://durgical.com/en/general-pathology/gallstones-cholesterol-vs-pigment/)
- [Cholecystitis: acute, acalculous and chronic](https://durgical.com/en/general-pathology/cholecystitis-acute-acalculous-and-chronic/)

## Related conditions 1

- [Gallstones (cholelithiasis)](https://durgical.com/en/conditions/gallstones/)

[← All of general pathology](https://durgical.com/en/general-pathology/)

Educational content on the mechanisms of disease; not a diagnostic or treatment guide and no substitute for a health professional's advice. No doses are given.

Sources: [Gallstones (Cholelithiasis)](https://www.ncbi.nlm.nih.gov/books/NBK459370/) (StatPearls (NCBI Bookshelf), 2026).

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Representative model, for educational purposes only.

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License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/general-pathology/congenital-anomalies-of-the-gallbladder/