Biliary ascariasis in a non-endemic region: A case report.

Over one billion people worldwide are affected by Ascaris lumbricoides. While ascariasis is rare in Saudi Arabia, it is occasionally encountered among expatriates from endemic regions. We report a case of biliary ascariasis in a 29-year-old female expatriate, highlighting the clinical, laboratory, radiological, and endoscopic retrograde cholangiopancreatography (ERCP) findings, with particular emphasis on the diagnostic role of imaging. The patient presented to the emergency department with right upper quadrant abdominal pain, although physical examination was unremarkable. Abdominal ultrasound revealed diffuse dilatation of the intra- and extrahepatic biliary tree, with a long, mobile, echogenic structure within the common bile duct, lacking acoustic shadowing. Magnetic resonance cholangiopancreatography (MRCP) confirmed the presence of intraductal Ascaris extending into the intrahepatic ducts. The patient was started on antiparasitic therapy and had an uneventful recovery. This case underscores the essential role of imaging in diagnosing biliary ascariasis, particularly when clinical and laboratory findings are nonspecific.