An intrahepatic gallbladder is a rare anatomical variation where the gallbladder is located within the liver tissue itself, rather than in its typical position on the liver’s surface. Normally, the gallbladder rests in a shallow depression on the underside of the liver. In contrast, an intrahepatic gallbladder is partially or completely embedded within the liver parenchyma.
How It Forms
An intrahepatic gallbladder forms during fetal development. The gallbladder typically develops as an outgrowth from the hepatic diverticulum, which is part of the primitive foregut, around the third week of gestation. During the second month, the gallbladder is normally an intrahepatic structure before it migrates to its usual superficial position on the liver’s underside. An intrahepatic gallbladder results from a developmental anomaly where this migration fails to occur completely. The gallbladder remains encased within the developing liver tissue, making it a congenital condition.
Recognizing and Diagnosing It
An intrahepatic gallbladder is often asymptomatic and often discovered incidentally during imaging studies for other reasons. When symptoms do occur, they can resemble those of a normally positioned gallbladder, such as pain in the upper right abdomen or nausea, especially if complications arise. However, symptomatic presentations are less common.
When an intrahepatic gallbladder is suspected, various imaging techniques are used. Ultrasound is often the initial and most common method, as it is non-invasive and effective at identifying the gallbladder’s location and any associated issues like gallstones. Computed tomography (CT) scans can provide more detailed cross-sectional images, helping to confirm its intrahepatic location and assess its relationship to surrounding structures. Magnetic resonance imaging (MRI) and magnetic resonance cholangiopancreatography (MRCP) offer greater soft tissue contrast and can visualize the biliary tree, useful for identifying the gallbladder within the liver parenchyma and ruling out other anomalies.
What Happens Next
If an intrahepatic gallbladder is asymptomatic, it does not necessitate specific treatment. It is generally regarded as a benign anatomical variation. However, the unique positioning of an intrahepatic gallbladder can lead to impaired function, as it may not empty completely. This incomplete emptying can result in bile stasis, increasing the likelihood of gallstone formation. Studies suggest that around 60% of intrahepatic gallbladders are associated with gallstones.
Although rare, potential complications include inflammation of the gallbladder (cholecystitis), often due to gallstones. The intrahepatic location can complicate the diagnosis and surgical management of these compared to a normally positioned gallbladder. In very rare cases, long-standing issues like chronic inflammation or gallstones might be associated with a slightly increased risk of more severe conditions, such as a liver abscess or certain types of tumors. For most individuals, an intrahepatic gallbladder is a finding that primarily requires awareness rather than active treatment, and regular follow-up is typically not indicated unless symptoms emerge.