Use of indium-111-labeled autologous leukocytes in differentiating pancreatic abscess from pseudocyst

Pancreatic abscess is very difficult to diagnose and to differentiate from pancreatic pseudocyst based on clinical findings, laboratory studies and roentgenographic examinations. Eight patients diagnosed as having a pancreatic mass by ultrasonography or computed tomography also underwent indium-111-labeled autologous leukocyte scanning (10 scans) for suspected intraabdominal sepsis. This scan detects migration of labeled leukocytes into abscesses or areas of inflammation. Four patients had abscess and positive scans, and four patients had pseudocyst and negative scans. There was one false-positive scan in a patient with a recurrent pancreatic mass after drainage of an abscess. Since pancreatic abscess requires prompt drainage, and since it may be preferable to delay drainage of a pseudocyst, the differentiation of these two conditions is important. This test appears very effective in diagnosing pancreatic abscess and differentiating it from a pseudocyst.