Which of the following gallbladder abnormalities is not always pathological in origin?

Biliary sludge refers to a mixture of particulate matter and thickened bile that can form within the gallbladder. It is important to note that while biliary sludge may sometimes accompany pathological conditions, such as in the case of cholecystitis or cholelithiasis, it is not exclusively indicative of disease.

Biliary sludge can occur in otherwise healthy individuals and may form due to factors such as fasting, pregnancy, or as a result of certain medications. This transient nature of biliary sludge allows it to be present in a non-pathological state, distinguishing it from other conditions like cholecystitis or cholelithiasis, which are inherently abnormal processes characterized by inflammation or the presence of gallstones, respectively.

Adenomyomatosis, while it is considered a benign alteration of the gallbladder wall, is also a recognized pathological condition. Unlike biliary sludge, which can appear in healthy gallbladders, adenomyomatosis is usually diagnosed based on imaging findings and indicates a change in tissue organization rather than a simple physiological state. Thus, biliary sludge is the only option among the listed abnormalities that can exist without a pathological basis.