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Ectopic Gall bladder

Posted Tue, 04/06/2010 - 18:01 by Eranga Perera

Images

Figure 1A

Figure 1B

Figure 2B

Clinical History:

A 93 year old female present with sudden onset of abdominal pain. Imaging studies were done to exlude Abdominal Aortic dissection.

Findings:

Figure 1A and 1B; Grey scale ultrasound scan of right hypochondrium show gall bladder (GB) in abnormal position compared with the liver (L). Figure 2A and 2B; CT scan of the abdomen axial (figure 2A) and coronal (figure 2B) sections demonstrate the ectopic gall bladder (arrow) subcapsular in position, causing mild indentation of the liver surface.

Diagnosis:

Ectopic Gall bladder.

Discussion:

Normal development of the gall bladder is from a diverticulum arising from the ventral foregut caudal to the stomach. The diverticulum further divides into cranial and caudal parts and the gall bladder and extrahepatic bile ducts develop from the caudal segment. The ectopic location of the gall bladder is thought to be due to abnormal migration of the caudal segment [1]. The normal gall bladder lies in the gall bladder fossa on the inferior surface of the liver in between the right and left hepatic lobes [2]. In imaging gall bladder can be identified by the relationship of the gall bladder neck anterior to the right branch of the portal vein. On CT images a well distended gall bladder measures 4 to 5cm in diameter on tranceverse scans and when collapse it appears as a smaller tubular structure. The wall thickness of normal gall bladder ranges from 1 to 3.5 mm. Enhancement of the wall with IV contrast is seen on CT and MR is normal and the density of the gallbladder lumen equals that of water [2]. Multiple congenital variants and anomalies are identified with the development of gall bladder such as agenesis of gall bladder, duplication of gall bladder, Phrygian cap, multiseptated gall bladder, diverticula, wandering gall bladder and ectopic gall bladder [2]. Ectopic gall bladder is a rare occurrence with an incidence of .1 to .7%. Ectopic gall bladder can be located in various positions such as, intrahepatic, within the lesser omentum, retroduodenal, within falciform ligament, abdominal wall muscles and in thoracic cavity [1,2]. The intrahepatic gall bladder is completely surrounded by hepatic parenchyma and commonly lies in a subcspsular location along the anterior inferior aspect of the right hepatic lobe. The gall bladder also can be displaced or rotated abnormally due to hypoplasia, aplasia, atrophy or hypertrophy of one of the hepatic lobes [2]. Although the anomalies of the gall bladder is relatively rare it is important to identify their abnormal positions especially when they are associated with cholelithiasis where the signs of cholecystitis would be misleading to the surgeon, and to prevent a possible damage to the biliary system in laparoscopic procedures [1].

References / Suggested Reading:

1.SW Lobo, RG Menezes, S Mamata, P Baral, T Kanchan, AV Bodhe and NB Bhat. Ectopic partial intrahepatic gall bladder with cholelithiasis-A rare anomaly. A case report. 2.John R, Haaga, MD,FACR,FSIR. Vikram S. Dogra, MD. Michael Frosting, MD, PhD. Murali Sundaram. CT and MRI of the whole body-5th edition.

Author

Eranga Perera, Shweta Bhatt,MD, Vikram S Dogra,MD.

Research assistant

University of Rochester.