[Case of retroperitoneal fibrosis after surgical treatment of autoimmune pancreatitis].

We present a case of retroperitoneal fibrosis (RPF) in a 72-year-old man who previously received pancreatectomy for autoimmune pancreatitis. He had received colectomy for early colon cancer on 11th November, 2005. During the routine follow-up for colon cancer, a swollen pancreas tail was detected on enhanced CT. He received distal pancreatectomy under the diagnosis of pancreas cancer on 4th October, 2007. Pathological diagnosis revealed the autoimmune pancreatitis. Eight months later, right hydronephrosis was observed in an abdominal ultrasonographic study, and at the same time, right hydroureterosis due to retroperitoneal soft tissue mass around the bifurcation was detected on enhanced CT. He was treated with predonisolone aiming at the diagnosis and/or therapy. Twelve weeks later, right hydronephrosis had disappeared and retroperitoneal mass had shrunken. Now, it is thought that autoimmune pancreatitis is a systemic sclerosing disease accompanied with extra-pancreatic pathologic changes such as RPF.