Question: A 75-year-old man, an opium addict for 30 years, presented with episodes of upper abdominal pain for 6 months. Investigations revealed hemoglobin, 14.6 gm%; TLC, 8600; DLC polymorphs, 65%; lymphocytes, 35%; blood urea, 35 mg/dL; serum creatinine, 1.4 mg/dL; serum bilirubin, 1.6 mg/dL (0.4 mg conjugated and 1.2 mg unconjugated); aspartate aminotransferase, 68 U/L (normal, 14–40); alanine aminotransferase, 78 U/L (normal, 10–40); and alkaline phosphatase, 185 U/L (normal, 38–126). Abdominal ultrasound revealed a dilated common bile duct (CBD) and pancreatic duct (PD). A side-viewing endoscopy showed normal ampulla (Figure A). Radial endoscopic ultrasound (EUS) images are shown in Figures B and C. A hypoechoic area (6.3 × 5.7 mm size) surrounding the lower part of CBD and PD was consistently noted just outside the duodenal wall in the prepapillary area (Figure D; Video 1). What is the diagnosis? What is the cause of this hypoechoic area? See the Gastroenterology web site (www.gastrojournal.org) for more information on submitting your favorite image to Clinical Challenges and Images in GI. The double duct sign (DDS) consists of simultaneous dilatation of the CBD and PD, usually owing to malignancy involving lower part of CBD and PD. Benign causes include chronic pancreatitis and sphincter of Oddi dysfunction (SOD).1Ahualli J. The double duct sign.Radiology. 2007; 244: 314-315Crossref PubMed Scopus (46) Google Scholar Opiate-induced SOD as a clinical entity has been described in patients with chronic opium addiction (COA).2Sharma S.S. Sphincter of Oddi dysfunction in patients addicted to opium: an unrecognized entity.Gastrointest Endosc. 2002; 55: 427-430Abstract Full Text Full Text PDF PubMed Scopus (40) Google Scholar, 3Wu S.D. Zhang Z.H. Jin J.Z. et al.Effects of narcotic analgesic drugs on human Oddi's sphincter motility.World J Gastroenterol. 2004; 10: 2901-2904Crossref PubMed Scopus (56) Google Scholar EUS is useful in the diagnostic evaluation of patients with DDS, especially where side-viewing endoscopy shows no tumor at the ampulla. EUS findings in this patient with COA, who presented with DDS, showed hypertrophy of the prepapillary sphincter, which gave an appearance of a tumor in periampullary area just outside the duodenal wall. EUS was clearly able to show the normal passage of both the CBD and the PD through this hypoechoic area (Video 1). Endoscopic retrograde cholangiography revealed normal CBD at the lower end and endoscopic sphincterotomy (ES) was performed (Video 2). In this case, the prepapillary sphincter was hypertrophied and EUS was helpful in ruling out the hypoechoic sphincter as malignant. Thereafter, the patient was selected for endoscopic retrograde cholangiopancreatography (ERCP) and ES. To summarize, EUS may be useful for evaluation of SOD owing to COA before therapeutic ERCP. Download .mpg (15.85 MB) Help with mpg files Video 1 Download .mpg (7.6 MB) Help with mpg files Video 2