Hepatoid adenocarcinoma of the extrahepatic duct

Enteroblastic cholangiocarcinoma: An uncommon, underrecognized subtype of bile duct cancer

Enteroblastic carcinoma is clinically characterized by an elevated serum level of alpha-fetoprotein (AFP) and is histologically characterized by cancer cells with a clear cytoplasm and 'blastic' coarse chromatin. It sometimes has an element of hepatoid carcinoma; therefore, these two neoplasms are often regarded as sister entities. Although hepatoid carcinoma in the biliary tree has been reported, enteroblastic cholangiocarcinoma is extremely uncommon. In the present study, four cases of enteroblastic cholangiocarcinoma were examined. Tumors were located inside the liver (n = 2) or common bile duct (n = 2). The two intrahepatic cases had a history of primary sclerosing cholangitis, and serum AFP levels were elevated in both. One unresectable case was diagnosed by needle liver biopsy, while the remaining three underwent surgical resection. Histologically, all cases showed similar microscopic features. Cuboidal or polygonal cancer cells with the characteristic clear cytoplasm and subnuclear vacuoles were arranged in a papillary, micropapillary, tubular, or solid architecture. One case had an element of pancreatobiliary-type adenocarcinoma, while a hepatoid carcinoma element was not observed in any cases. All cases were positive for AFP, glypican 3, and SALL4, with SALL4 being the most widely expressed. Heppar-1 and arginase-1 were negative, except for one case, which was positive for Heppar-1. In conclusion, enteroblastic cholangiocarcinoma is an uncommon subtype of biliary tract malignancy. These cases may have been categorized as 'clear cell' cholangiocarcinoma. Although enteroblastic cholangiocarcinoma seems to occur more commonly in extrahepatic regions, including the gallbladder, it may also develop in the liver, particularly in patients with primary sclerosing cholangitis.

Hepatoid tumors of the gastrointestinal/pancreatobiliary district: morphology, immunohistochemistry, and molecular profiles

Hepatoid tumors (HTs) histologically resemble hepatocellular carcinoma (HCC) but manifest outside the liver. Regarding immunohistochemistry (IHC), the classical markers of hepatoid differentiation are Hep Par-1, CD10, and arginase-1. This study provides a critical overview of HT in the gastrointestinal/biliopancreatic system, which is the most common site of origin. Gastric HTs are malignant neoplasms recognized by the current WHO classification as a variant of adenocarcinoma. In addition to the classic IHC markers, SALL4 and claudin-6 can help exclude a metastatic HCC at this site. Next-generation sequencing revealed the most common alterations, including TP53 mutation, microsatellite instability (MSI), and Her2 amplification. Esophageal HTs are exceptionally rare and usually arise in the context of Barrett's esophagus. In the intestine, HTs are classified within the adenocarcinoma spectrum and manifest more often in the background of inflammatory bowel disease. Regarding their molecular profile, recurrent alterations included MSI and NCOA4-RET fusions. In the pancreas, the current WHO classification acknowledges HT only as a possible variant of ductal adenocarcinoma, characterized by a poor prognosis. However, at this site, neuroendocrine tumors (NETs) and solid pseudopapillary neoplasms (SPNs) may also show hepatoid differentiation. Hepatoid NETs show aggressive behavior, whereas hepatoid SPNs harbor CTNNB1 mutations and are characterized by an indolent clinical course. Lastly, biliary HTs belong to the adenocarcinoma category and usually show a poor prognosis. In conclusion, gastrointestinal/pancreatobiliary HTs show specific histomolecular features, which should be considered for improving routine diagnostic activity and clinical management.

Cholangiocarcinoma

Liver cancer represents the third leading cause of cancer-related death worldwide. Cholangiocarcinoma (CCA) is the second most common type of liver cancer after hepatocellular carcinoma, accounting for 10-15% of all primary liver malignancies. Both the incidence and mortality of CCA have been steadily increasing during the last decade. Moreover, most CCAs are diagnosed at an advanced stage, when therapeutic options are very limited.

CCA may arise from any tract of the biliary system and it is classified into intrahepatic, perihilar, and distal CCA, according to the anatomical site of origin. This topographical classification also reflects distinct genetic and histological features, risk factors, and clinical outcomes. This review focuses on histopathology of CCA, its differential diagnoses, and its diagnostic pitfalls.

Hepatoid Adenocarcinoma of the Extrahepatic Bile Duct in a Patient with Polysplenia Syndrome

Hepatoid adenocarcinoma (HAC) is a rare subtype of extrahepatic adenocarcinoma that is characterized by its morphological and functional similarities to hepatocellular carcinoma. We herein present a novel case of HAC arising from the extrahepatic bile duct in a 75-year-old Japanese woman with polysplenia syndrome. This is the second reported case of HAC arising from this site. The tumor induced jaundice and hemobilia. A total of four isolated intraductal polypoid masses of HAC were found. No recurrence was seen five months after surgery. Further reports of similar cases will be needed to clarify the clinical characteristics and the prognosis of this malignancy.

Rare coexistence of mediastinal hepatoid adenocarcinoma, idiopathic azoospermia and horseshoe kidney: a case report and review of the literature

Hepatoid adenocarcinoma (HAC) is the term proposed for a special type of extrahepatic tumors, which is similar to the hepatocellular carcinoma (HCC) both in the histopathology and immunohistochemistry. HAC has been observed in the stomach, colon, pancreas, gall bladder, lung and female genital tract, but rarely in the mediastinum. Now we describe a case of a 28-year-old Chinese male with primary mediastinal HAC with lung and liver metastasis. In this patient, HAC was associated with horseshoe kidney and idiopathic nonobstructive azoospermia. It seemed derivation abnormalities during organogenesis in the embryo stage played a significant role in the pathogenesis of HAC, horseshoe kidney and idiopathic nonobstructive azoospermia. Even the pathogenesis was still unknown; it may merit consideration of HAC together with horseshoe kidney and idiopathic nonobstructive azoospermia as a syndrome rather than as a spectrum of coincidental diseases. Furthermore, we found the HAC is a neoplasm with unfavorable outcomes despite aggressive and multi-protocol strategies. The serum alpha fetoprotein (AFP) should be regarded as a useful marker for diagnostic purposes and therapeutic response evaluation of HAC.