Pitfall – Stones in the gall bladder – Adenomyomatosis

Images Ying Ying Lee, text Genevieve Carbonatto

A 44 year old man presents with acute abdominal pain. His pain is mainly epigastric but you are concerned about the possibility of cholecystitis, cholelithiasis or choledocholithiasis.

While scanning the patient in the supine position, you think you can see stones in the GB. They do not appear to be in the neck of the gall bladder.  You decide to stand the patient up to check whether this will better visualise the neck and whether the stones visible in the supine position will move. This is the scan of his gall bladder when he stands up

A string of pearls of tiny stones are visible casting an acoustic shadow at the posterior wall of the GB. The fundus of the gallbladder is thickened and there are tiny little echogenic foci within the thickened wall.

With colour Doppler, the tiny echogenic foci light up like a christmas tree.

These are comet tail or ring down artifact caused by the stones. These stones are within the wall of the gallbladder. The string of pearls visible in the supine position, have not moved when the patient stands up. This is adenomyomatosis of  the gallbladder.

Discussion

The first point to make is that not all GB wall thickening is due to cholecystitis. The second is that stones have clinical relevance in the patient presenting to the ED with pain only if they are in the neck of  the GB or have passed into the cystic duct or CBD. GB wall thickening can be due a number of causes other than cholecystitis. Some common causes of GB wall thickening are physiological (postprandial), non inflammatory (adenomyomatosis,carcinoma of the GB, leukaemia, multiple myeloma), oedema of the GB wall (ascites, hypoalbuminaemia, heart failure, portal hypertension), adjacent inflammatory disease (viral hepatitis, alcoholic hepatitis, acute pancreatitis). (1)

What is adenomyomatosis?

Adenomyomatosis of the GB is a benign condition found in 9% of patients post cholecystectomy and usually found incidently. It is characterised by

  1. GB wall thickening which is either genralised or diffuse, fundic or segmental (hour glass gallbladder) 

Schematic representation of adenomyomatosis adapted from Sleisenger and Fordtran’s Gastrointestinal and liver disease 9th ed p 1146 – 1149

2. Hyperplasia of the wall with the formation of Rokitansky Aschoff sinuses (intramural diverticulae lined by mucosal epithelium). For the histological diagnosis of  adenomyomatosis the Rokitansky – Aschoff sinuses need to be deep.

Sleisenger and Fordtran’s Gastrointestinal and liver disease 9th ed p 1146 – 1149

3. Precipitation of cholesterol crystals within the lumen of  Rokintansky -Aschoff sinuses. These crystals can calcify.

4. These cholesterol crystals produce V shaped comet tail artifacts which can be seen in 2D US and with Colour Doppler. With Colour Doppler you get a Christmas tree effect where the artifact emanates from the small crystals

Teaching point: Not all GB wall thickening is due to cholecystitis. Not all stones are within the GB lumen. Interpret your findings within the clinical context. To be clinically relevant, stones need to be within the neck of the GB . Unless stuck within the neck of the gallbladder, stones should move when the patient is rolled or stood up.

References

  1. Radiopaedia : Adenomyomatosis of the Gallbladder
  2. Sleisenger and Fordtran’s Gastrointestinal and liver disease 9th ed p 1146 – 1149
  3. Clinical ultrasound 3rd edition Allan, Baxter and Weston

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