What are the causes of a pseudo gallbladder in patients with a history of liver disease, abdominal surgery, or certain infections?

Causes of Pseudo Gallbladder

Pseudo gallbladder refers to imaging findings that mimic a gallbladder but represent other anatomical structures or pathological conditions, most commonly seen in patients with liver disease, biliary obstruction, or inflammatory processes.

Primary Causes in Liver Disease and Biliary Pathology

Primary Sclerosing Cholangitis (PSC)

• Gallbladder abnormalities occur in up to 41% of PSC patients, including wall thickening and gallbladder enlargement that can create pseudo-gallbladder appearances on imaging 1
• PSC is strongly associated with inflammatory bowel disease in 60-80% of cases, predominantly ulcerative colitis 2, 3
• Cholangiographic findings show multifocal strictures with segmental dilatations creating a "beaded" pattern that can be confused with other biliary structures 2
• Secondary sclerosing cholangitis from previous biliary surgery, surgical trauma from cholecystectomy, intraductal stone disease, intra-arterial chemotherapy, and recurrent pancreatitis can all produce similar imaging abnormalities 1, 2

IgG4-Associated Cholangitis

• IgG4-associated cholangitis mimics PSC but shows long biliary strictures with prestenotic dilatations that can create pseudo-gallbladder appearances on imaging 2
• Serum IgG4 >4× upper limit of normal is highly specific, though 9-15% of PSC patients also have elevated IgG4 levels 2
• This condition responds dramatically to corticosteroids, unlike PSC 2, 3

Ischemic and Infectious Cholangitis

• Ischemic cholangitis can produce biliary strictures and dilatations that mimic gallbladder structures 1, 2
• AIDS cholangiopathy creates characteristic biliary changes that can be confused with gallbladder pathology 1
• Recurrent pyogenic cholangitis produces biliary dilatations and strictures 1, 2

Causes Related to Abdominal Surgery

Post-Surgical Biliary Changes

• Surgical trauma from cholecystectomy is one of the most common causes of secondary sclerosing cholangitis that can create pseudo-gallbladder appearances 1, 2
• Previous biliary surgery can produce strictures and dilatations mimicking gallbladder structures 1
• Abdominal injury can lead to biliary tract changes that create confusing imaging findings 1

Portal Hypertensive Biliopathy

• Portal hypertensive biliopathy produces biliary tract changes in patients with liver disease that can mimic gallbladder pathology 1

Anatomical Variants and Inflammatory Conditions

Gallbladder Anatomical Variants

• Gallbladder folds can create unique visual patterns on imaging that mimic duplication or associated choledochal cysts 4
• Interposition of the gallbladder (absent common hepatic duct and cystic duct) presents with dilated intrahepatic ducts adjacent to a normal or enlarged gallbladder, mimicking choledochal cyst, hydrops, or Caroli's disease 5
• Grossly enlarged gallbladder fused to the inferior surface of the liver can create confusing imaging appearances 6

Chronic Inflammatory Conditions

• Honeycomb gallbladder represents a pseudo-multiseptate gallbladder associated with chronic cholecystitis, showing multiloculated appearance on CT that can be mistaken for other structures 7
• Xanthogranulomatous cholecystitis can involve the liver and adjacent organs, clinically mimicking gallbladder carcinoma and creating pseudo-gallbladder appearances 8

Other Biliary Pathology

Cystic Lesions and Malformations

• Hepatic inflammatory pseudotumor can create biliary changes mimicking gallbladder structures 1
• Caroli disease and biliary hamartomas represent ductal plate malformations that can be confused with gallbladder pathology 2
• Choledochal cysts can mimic gallbladder structures on imaging 5

Obstructive Causes

• Choledocholithiasis with biliary dilatation can create pseudo-gallbladder appearances 1
• Cholangiocarcinoma produces strictures and dilatations that may mimic gallbladder structures 1, 2

Critical Diagnostic Pitfalls

• Cross-sectional anatomic imaging with CT or ultrasound is essential to differentiate true gallbladder from pseudo-gallbladder, as scintigraphy alone can be misleading with variant anatomy 4
• Absence of biliary dilatation does not exclude obstruction in acute presentations 2
• MRCP is the cornerstone for identifying biliary obstruction and characteristic patterns to distinguish pseudo-gallbladder from true pathology 2
• Intraoperative biopsy may be necessary when imaging features suggest extensive disease that appears inoperable 8