A 78 year old male presents with jaundice associated with increased itching and a palpable gall bladder. Possible diagnosis is -

Ans. is 'a' i.e., Periampullary carcinoma o Courvoisier's law states that in the presence of an enlarged gall bladder which is nontender and accompanied with jaundice the cause is unlikely to be gallstones. This is because gall stones are formed over a longer period of time, and this result in a shrunken, fibrotic gall bladder which does not distend easilyo In contrast, the gall bladder is more often enlarged in pathologies that cause obstruction of the biliary tree over a shorter period of time such as malignancy of bile duct, pancreas, leading to passive distention from backpressure.