Courvoisier sign

The underlying principle (Courvoisier's law) states that gradual, chronic obstruction of the common bile duct—typically by a malignancy such as pancreatic head adenocarcinoma, cholangiocarcinoma, or ampullary carcinoma—allows the gallbladder to distend slowly and painlessly, becoming palpable on exam. This is in contrast to obstruction caused by gallstones, where chronic inflammation and fibrosis (from repeated cholecystitis) render the gallbladder wall thickened, fibrotic, and non-distensible, so it typically cannot enlarge even if the duct becomes obstructed. Clinically, a patient presents with painless jaundice, a palpable right upper quadrant mass, and possibly weight loss—raising concern for periampullary or pancreatic malignancy rather than choledocholithiasis. However, it's important to note that Courvoisier sign is not universally reliable—some cases of gallstone disease can present with a palpable gallbladder, and not all pancreatic cancers cause a palpable gallbladder. Diagnostic workup includes abdominal ultrasound or CT to evaluate the biliary tree, gallbladder, and pancreas, along with tumor markers (CA 19-9) and possibly ERCP or MRCP for further characterization. This finding is a classic board-relevant clue tying together bilirary anatomy, pancreatic cancer presentation, and the pathophysiologic distinction between malignant vs. stone-related obstruction.