Double duct sign

The double duct sign refers to the presence of simultaneous dilatation of the common bile and pancreatic ducts. Being an anatomical sign it can be seen on all modalities that can visualize the region, including: MRI, CT, ultrasound and endoscopic retrograde cholangiopancreatography (ERCP). In general, the double duct sign represents a malignant cause until disproved.

Pathology

Etiology

Common

• carcinoma of the head of the pancreas

• ampullary tumors (e.g. carcinoma of the ampulla of Vater)

Less common

• malignant

  • cholangiocarcinoma involving distal common bile duct

  • lymphoma

  • ampullary metastases

• impacted gallstone in distal duct, with associated edema, resulting in pancreatic duct obstruction

• chronic pancreatitis

• ampullary stenosis

Rare

Case reports ^1-3

• primary retroperitoneal fibrosis

• Kaposi sarcoma

• sphincter of Oddi dysfunction ³