Intrahepatic bile duct mixed adenoneuroendocrine carcinoma: a case report and review of the literature

Abstract

Background: Mixed adeno-neuroendocrine carcinoma (MANEC) of the biliary tract is rare with only a few reported cases. Consequently, knowledge about their pathogenesis, histopathological characteristics and outcomes is sparce.

Case presentation: A 53-year old man presented with epigastric pain on a background of excessive alcohol consumption. Contrast-enhanced computed tomography imaging of the liver revealed a central enhancing mass located at the bifurcation of right anterior and posterior portal veins. Magnetic resonance imaging demonstrated intrahepatic biliary duct dilatation distal to the mass. The patient underwent a right lobe hepatectomy and excision of the extrahepatic biliary tree with formation of a hepaticojejunostomy. Histopathological finding of the specimen revealed an intraductal tumour with predominant neuroendocrine immunohistochemical phenotype and infiltration into nearby tissue. An element of glandular differentiation on immunohistochemistry confirmed the lesion as MANEC.

Conclusions: We present the first reported histopathological case of a MANEC arising from the intrahepatic bile ducts. This report aims to review what is known about primary neuroendocrine and mixed adeno-neuroendocrine carcinoma of the bile ducts, particularly in comparison to other types of biliary and hepatic tumours.

Fig. 1

Dual phase abdominal contrast CT scan. Tumour at the bifurcation of the right anterior and posterior portal vein (arrow). Enhancement of lesion during arterial phase (a), with mild contrast washout in portal venous phase (b). Liver shows background steatosis

Fig. 2

MRCP. Arterial phase demonstrating enhancement of tumour (arrow) (a), with images at 120 s post-contrast demonstrating washout of contrast (arrow) (b), and successive axial images at 10 min post-contrast showing dilatation of interlobular bile ducts (arrowhead) (c, d, e)

Fig. 3

Low magnification view of intraductal (a) and periductal invasive component (b). H&E 20×

Fig. 4

Intraductal component showing strong and diffuse staining for synaptophysin (a and b) and chromogranin (c and d)

Fig. 5

Ki67 analysis estimated to be up to 8 % with up to three mitotic figures present in 50 HPF

Fig. 6

High magnification view of part of the lesion showing clarification of the cytoplasm and signet ring morphology. H&E 400×

Fig. 7

Alcian blue diastase PAS. Tumour cells with signet ring morphology showing weak cytoplasmic staining. 400×

Fig. 8

Numerous tumour cells in the areas showing signet ring morphology stain for MUC-1. 30×

Fig. 9

CA19.9 staining highlights the superficial component of the intraductal-growing tumor, most likely residual biliary epithelium

Fig. 10

Hep-Par1 staining showing negative hepatocellular tumour differentiation, with normal adjacent liver parenchymal staining (top right)