Mirizzi syndrome demonstrates which characteristic?

Mirizzi syndrome is a condition characterized by the obstruction of the common hepatic duct due to an impacted gallstone in the cystic duct or the neck of the gallbladder. This results in extrahepatic biliary obstruction, which can lead to secondary changes in the surrounding structures.

The correct characteristic of Mirizzi syndrome is that the common bile duct remains normal in terms of its structure and function at the time of diagnosis. In patients with this syndrome, the common bile duct may not show any unusual enlargement or changes directly as a result of the condition itself, although it can be obstructed due to the impacted stone.

Understanding this concept is vital in the diagnosis and management of patients with gallbladder-related issues, as it highlights the unique nature of the syndrome, where the obstruction originates not from a primary pathology in the common bile duct itself but rather from issues higher up in the biliary system. Such knowledge helps differentiate Mirizzi syndrome from other biliary obstructions that would typically present with a dilated common bile duct.