{
  "abstract": "Introduction Primary well-differentiated neuroendocrine tumours (NETs) of the biliary tract (BTNETs) are exceptionally rare, with only sporadic reports, mostly single case reports, available. Tumour cell phenotypes and molecular abnormalities in BTNETs are largely unknown. The present study aimed to elucidate the clinicopathological characteristics of BTNETs using immunohistochemistry for DAXX and ATRX, which serves as a surrogate marker for mutations in these genes.Methods Ten cases of BTNETs diagnosed and treated between 2011 and 2014 were identified from pathology archives. Clinicopathological and demographic parameters were collected. Immunohistochemistry was performed to evaluate tumour cell lineage using TTF1, CDX2, ISL1 and NKX6.1, and to assess nuclear expression of DAXX and ATRX.Results The ten-case cohort comprised five female and five male patients with a median age of 59 years. Tumours were located in the common bile duct (n=4), hepatic duct (n=3), cystic duct (n=2) and gallbladder neck (n=1). In six cases, BTNETs were incidentally identified in surgical specimens resected for other purposes (tumour size 2–6 mm), while BTNET was the primary diagnosis in the remaining four cases (tumour size 11–31 mm). Nine cases were pure NETs, while one case contained an adenocarcinoma component comprising 10% of the tumour. None demonstrated features of poorly differentiated neuroendocrine carcinoma. BTNETs were graded as G1 (n=7) and G2 (n=3). Eight cases underwent surgical resection, while the remaining two were inoperable due to liver metastases and a locally advanced tumour at the hepatic hilum, requiring chemotherapy. All cases expressed chromogranin A and synaptophysin. BTNETs were also positive for CDX2 (n=4), ISL1 (n=7), and NKX6.1 (n=5), with at least one islet marker (either ISL1 or NKX6.1) positive in all cases tested. All assessed cases demonstrated retained nuclear expression of DAXX and ATRX, indicating the absence of mutations in these genes.Conclusion BTNETs are rare neoplasms, and fewer than 50% of cases present with a clinically apparent tumour. BTNETs share cellular phenotypes with pancreatic NETs; however, unlike pancreatic NETs, mutations in DAXX and ATRX appear to be uncommon.",
  "authors": [
    {
      "affiliations": [
        "GKT School of Medicine, King’s College London, London, United Kingdom"
      ],
      "name": "Rawan Talea"
    },
    {
      "affiliations": [
        "GKT School of Medicine, King’s College London, London, United Kingdom"
      ],
      "name": "Zainab Shirazi"
    },
    {
      "affiliations": [
        "Institute of Liver Studies, King’s College Hospital, London, United Kingdom"
      ],
      "name": "Yoh Zen"
    }
  ],
  "title": "P155 Well differentiated neuroendocrine tumours in the biliary tract: a clinicopathological and immunohistochemical study of 10 cases",
  "uid": "6e737f75-55c3-5574-9a44-7a3a5a34bbd4"
}