AB057. P-25. Clinicopathologic features of intraductal tubulopapillary neoplasms of the bile duct

Background: Intraductal tubulopapillary neoplasms (ITPN) of the bile duct are a newly described entity in the family of biliary malignant lesions. They are characterized histologically by almost exclusive tubular growth within the bile duct. Given their rarity, information on biologic behavior and clinical features is limited. We describe the natural history of two consecutive patients diagnosed with ITPN of the bile duct.

Methods: Cases were identified by dedicated pathologic review of biliary resection specimens. Patient demographic data including medical history, presenting symptoms, tumor markers, imaging features, pathologic findings, and survival were obtained from the medical record.

Results: Both patients were male, diagnosed at age 64 and 50. Both presented with pruritus, jaundice, and increased liver function tests. CA19-9 levels were elevated at 256 and 137. CT scan showed intrahepatic biliary ductal dilatation from intrabiliary masses. The 64-year-old patient had an obstructing mass visualized in the common hepatic duct (CHD) abutting the confluence of the right and left hepatic duct without evidence of vascular involvement. The 50-year-old also had a large obstructing mass in the proximal CHD with abutment of the right hepatic artery and portal vein. MRCP images were similar, demonstrating soft tissue masses in the proper hepatic duct with polypoid intraductal extension into the left hepatic duct. Tumors measured 4.0 cm × 2.5 cm and 2.5 cm × 1.9 cm. Following complete staging both patients underwent a liver resection [(I) left hepatectomy, caudate, and bile duct resection; (II) extended right hepatectomy, caudate, and bile duct resection). Both patients had portal lymphadenectomies and hepaticojejunostomy reconstruction. Final pathology of both patients revealed pT1N0 invasive adenocarcinoma arising in association with an ITPN and high-grade dysplasia. Neither patient received adjuvant chemotherapy. The patients are alive at 23 and 1.5 months without evidence of disease.

Conclusions: Patients with ITPN of the bile duct present with biliary obstruction with tumors showing significant intraductal tubular growth. Despite the presence of invasive carcinoma, no LN metastases were seen and both patients had early stage disease. Further study is necessary to determine whether malignancy arising in the setting of ITPN is associated with more favorable survival compared to conventional hilar cholangiocarcinoma.

Keywords: Intraductal tubulopapillary neoplasm; intraductal papillary neoplasm of the bile duct (IPNB); cholangiocarcinoma; intraductal