Definition: Given an abstract, generate a keyword (a noun phrase) that best describes the focus or contribution of the paper. Such keywords can be directly from the given abstract or outside it.
Input: Abstract: Congenital cystic dilatation of the biliary tree (Caroli's disease) is a rare condition that usually presents with ascending cholangitis. This report demonstrates the difficulty of recognizing other complications of Caroli's disease antemortem. A 35-year-old man developed a subphrenic abscess and malignant transformation of the biliary tree; both were clinically undetected. Episodes of pain, pyrexia, or weight loss should be assessed carefully and the complications of Caroli's disease considered before attributing such symptoms to recurrent cholangitis.
Output:

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
Adult