title: An inguinal hernia sac tumor of extrahepatic cholangiocarcinoma origin.
abstract: BACKGROUND
  Metastatic hernia sac tumor from biliary malignancy is extremely rare with only one such case previously reported. We herein report an additional case of extrahepatic cholangiocarcinoma presenting as a hernia sac tumor.
  
  
  METHODS
  A 78-year-old man presented with an irreducible right inguinal hernia associated with a firm tumor, 2.0 cm in diameter. A computed tomography scan demonstrated a soft tissue density mass with heterogeneous enhancement within the right inguinal canal. The patient underwent a hernia repair and the hernia sac tumor was resected. Histological examination of the tumor revealed a metastatic adenocarcinoma suggesting the tumor was of pancreato-biliary origin. Further investigation using imaging studies disclosed a primary tumor in the upper bile duct. The patient died of the disease nine months after the resection.
  
  
  CONCLUSIONS
  Hernia sac tumors should be considered when an irreducible, growing mass appears within an inguinal hernia. Computed tomography may be useful for the early detection of hernia sac tumors from undiagnosed intra-abdominal malignancies.
authors.affiliation: Division of Digestive and General Surgery, Niigata University Graduate School of Medical and Dental Sciences, Asahimachi-dori 1-757, 951-8510, Niigata, Japan. yokonao@med.niigata-u.ac.jp
authors.forename: Naoyuki
authors.initials: N
authors.lastname: Yokoyama
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Shirai
authors.forename: Hidehiro
authors.initials: H
authors.lastname: Yamazaki
authors.forename: Katsuyoshi
authors.initials: K
authors.lastname: Hatakeyama