Intraductal Papillary Neoplasm of the Bile Duct: A Rare Case of Intrahepatic Space-Occupying Lesion

Abstract

Intraductal papillary neoplasm of the bile duct (IPNB) is a rare tumor and is considered one of the precursor lesions for cholangiocarcinoma. Though relatively common in the far east countries, it is uncommon in the Indian population. A 67-year-old gentleman presented with vague upper abdominal pain with no history of fever, jaundice, melena, or hematemesis. An abdominal ultrasound showed a solid cystic lesion in the left lobe of the liver with upstream dilatation of bile ducts. Computed tomography and magnetic resonance imaging showed similar findings. With a differential diagnosis of intrahepatic cholangiocarcinoma, intraductal papillary neoplasm, and biliary cystadenoma, he underwent robotic-assisted left hepatectomy. Histopathology was suggestive of IPNB. Following surgery, he had an uneventful recovery and was advised for follow-up visits every six months. A clinical, radiological, and pathological profile of this rare tumor has been described here with a review of the existing literature.

Keywords: biliary papillomatosis; bt-ipmn; cholangiocarcinoma; intraductal papillary neoplasm of bile duct; ipnb.

Figure 1. CT images. IPNB lesion is marked with a white arrow. Dilated left-sided biliary radicles are shown with white arrowheads. (A) Axial section, non-contrast (plain) phase; (B) axial section, arterial phase; (C) axial section, portal phase; (D) reconstructed coronal section, delayed phase.

CT, computed tomography; IPNB, intraductal papillary neoplasm of the bile duct

Figure 2. MRI images. (A) T1-weighted axial section with low to isointense lesion (white arrow); (B) T2-weighted axial section with hyperintense lesion with intraductal papillary projections (white arrow); (C) 3D volume reconstructed MRCP image showing the cystic lesion with communication with LHD which is causing proximal dilatations of the biliary ducts.

MRI, magnetic resonance imaging; MRCP, magnetic resonance cholangiopancreatography; RAD, right anterior sectoral duct; RPD, right posterior sectoral duct; GB, gall bladder; LHD, left hepatic duct

Figure 3. (A, B) Intraoperative robotic surgery images showing the nodular surface of the left lobe of the liver (black arrows) in contrast to the smooth surface of the right side; (C) resected specimen of the left lobe of the liver (posterior surface).

II, III, IVa, IVb, demonstrating the respective liver segments; IPNB, intraductal papillary neoplasm of the bile duct

Figure 4. Histopathological images. (A) Section showing a cystic lesion with a thin rim of liver parenchyma (painted end). The cyst is lined by columnar epithelium thrown into complex papillary processes, hematoxylin and eosin stain, ×40; (B) Section showing higher magnification of the lesion with stratified lining exhibiting prominent nucleoli, occasional mitoses, and moderate nuclear pleomorphism with evidence of intracytoplasmic mucin, hematoxylin and eosin stain, ×400; (C) Section showing tumor cells exhibiting spare cytoplasmic expression of cytokeratin 7. Immunohistochemistry with DAKO polyclonal antibody for cytokeratin 7, diaminobenzidine stain, ×200; (D) Section showing tumor cells exhibiting strong diffuse cytoplasmic expression of cytokeratin 19. Immunohistochemistry with DAKO polyclonal antibody for cytokeratin 19, diaminobenzidine stain, ×200.