[A Case of Peritoneal Dissemination of Hilar Cholangiocarcinoma Presenting with Hematuria Six Years after Radical Surgery].

A 76-year-old man underwent radical surgery for Stage IV a hilar cholangiocarcinoma in July 2009, and had been followed at an outpatient clinic. Although no apparent recurrent lesion was detected by PET/CT examination, an elevated CA19-9 level was found in January 2014. He was then started on the oral anticancer drug S-1. However, his CA19-9 level increased gradually. The patient presented to a urological department with a complaint of macrohematuria in May 2015. Detailed examination revealed a mass lesion at the top of the urinary bladder, which was suspected to be peritoneal dissemination of the known hilar cholangiocarcinoma invading the urinary bladder wall. Thus, he underwent partial resection of the urinary bladder in July 2015. A histopathological examination of the resected specimen confirmed the diagnosis of recurrence. The patient is nowreceiving chemotherapy with gemcitabine and cisplatin. Detection of recurrences of cholangiocarcinoma is often difficult since the recurrence pattern of cholangiocarcinoma varies widely. However, early detection might enable longterm survival by adequate treatment including chemotherapy. Therefore, thorough multidisciplinary examinations are required when recurrence of cholangiocarcinoma is suspected. In addition, long-term follow-up after radical surgery is required since cholangiocarcinoma sometimes shows slow progression.