{
  "abstract": "A 62-year-old man presented for evaluation after an abdominal ultrasound revealed dilation of the common bile duct and intrahepatic bile ducts without symptoms. His medical history was unremarkable. Alkaline phosphatase was 55 U/L (ref range: 38–113), γ-glutamyl transpeptidase 73 U/L (ref range: 13–64) and total bilirubin 0.9 mg/dL (ref range: 0.4–1.2). Tumour markers were normal, but IgG4 was mildly elevated at 137 mg/dL (ref range: 11.0–121.0). Enhanced abdominal CT ( figure 1) and magnetic resonance cholangiopancreatography (MRCP) (figure 2) were performed. CT showed bile duct wall thickening with contrast enhancement and an elevated distal bile duct lesion. MRCP showed a common bile duct stone and an intraductal elevated lesion. An endoscopic retrograde cholangiopancreatography (ERCP) (figure 3) was then performed, followed by a peroral cholangioscopy (POCS) (figure 4). On ERCP, in addition to a filling defect suggestive of common bile duct stone, an irregular surface ridge in the distal bile duct was identified as a thumb printing image. Subsequent POCS identified a papillary proliferating elevated lesion, but no tortuous or dilated vessels. Findings other than POCS and tumour markers were positively suggestive of cholangiocarcinoma. POCS-guided forceps biopsy, fluoroscopy-guided biopsy and biliary cytology were performed to further assess the lesion.",
  "authors": [
    {
      "affiliations": [
        "Kurume University School of Medicine, Kurume, Fukuoka, Japan"
      ],
      "name": "Sohei Yoshimura"
    },
    {
      "affiliations": [
        "Kurume University School of Medicine, Kurume, Fukuoka, Japan"
      ],
      "name": "Takahiko Sakaue"
    },
    {
      "affiliations": [
        "Kurume University School of Medicine, Kurume, Fukuoka, Japan"
      ],
      "name": "Hidetoshi Takedatsu"
    }
  ],
  "title": "Bile duct wall thickening in a 62-year-old man",
  "uid": "79fd2a07-b4f4-5c3f-b0d7-a650576f4c56"
}