<aside>

Intraductal Papillary Neoplasm of the Bile Duct (IPNB) is a precancerous intraductal epithelial tumor of the bile ducts characterized by exophytic papillary growth with fibrovascular stalks.

</aside>

• It is considered the biliary counterpart of Intraductal papillary mucinous neoplasm (IPMN) of the pancreas.
• Frequently associated with mucin hypersecretion, which can lead to ductal dilatation.
• Has potential to progress to cholangiocarcinoma.

Etiopathology

• Risk factors:
  • Hepatolithiasis
  • Recurrent pyogenic cholangitis
  • Parasitic infections (Clonorchis, Opisthorchis)
  • Choledochal cysts
  • Chronic biliary inflammation
• Histology:
  • Four epithelial subtypes:
    1. Pancreatobiliary (most common, high-grade dysplasia risk)
    2. Intestinal
    3. Gastric
    4. Oncocytic
  • Variable degrees of dysplasia; may progress to invasive adenocarcinoma.
  • IHC: CK7, CK19 positive; subtype markers (MUC1, MUC2, MUC5AC) can help classification.

Clinical Features

Epidemiology

• Seen more commonly in East Asia (due to hepatolithiasis and parasitic infections).
• Typically presents in the 5th–7th decade, slight male predominance.

Clinical presentation:

• Intermittent abdominal pain, jaundice, fever (cholangitis).
• Recurrent cholangitis due to mucin obstruction.
• Elevated CA 19-9 sometimes seen.

Radiology

<aside>

IPNB should be suspected when there is segmental or diffuse bile duct dilatation with an enhancing intraductal papillary mass and/or mucin hypersecretion, especially in a patient with hepatolithiasis or recurrent cholangitis.

</aside>