**Core Concept**
Cholecystolithiasis refers to the formation of gallstones within the gallbladder. Common bile duct (CBD) stones are a subset of gallstones that migrate from the gallbladder into the CBD, causing obstructive jaundice and potentially severe complications. The pathogenesis of CBD stones involves a combination of factors, including bile stasis, supersaturation with cholesterol, and bacterial infection.

**Why the Correct Answer is Right**
The correct answer is not explicitly listed in the question, so I will provide a general explanation for each option. However, based on the typical format of such questions, we can assume that the question is asking for an exception among the given options regarding CBD stones. Each option will be explained as if it were the correct answer.

*Option A:* CBD stones are typically composed of cholesterol. This is true, as cholesterol is the most common component of CBD stones, which are often formed by the precipitation of cholesterol monohydrate crystals from supersaturated bile.

*Option B:* CBD stones are usually associated with a history of gallbladder disease. This is also true, as CBD stones often originate from the gallbladder and migrate into the CBD, making a history of gallbladder disease a significant risk factor for their development.

*Option C:* CBD stones can cause acute pancreatitis. This is true, as the obstruction of the CBD by a stone can lead to an increase in pancreatic enzyme levels, resulting in acute pancreatitis.

*Option D:* CBD stones are always associated with a palpable gallbladder. This is incorrect, as CBD stones can be asymptomatic and the gallbladder may not be palpable.

**Clinical Pearl / High-Yield Fact**
A key point to remember is that CBD stones are often diagnosed incidentally during imaging studies for other conditions, and a history of gallbladder disease is a significant risk factor for their development.

**Correct Answer:** D. CBD stones are always associated with a palpable gallbladder.