RADIOLOGY: PANCREAS: Case# 34078: NECROTISING PANCREATITIS DUE TO MONOCLONAL ANTIBODY THERAPY. Patient is a 73 year old male being treated with monoclonal antibody to 171A for prostate cancer. He initially had prostectomy but has rising PSA. He was admitted with increasing abdominal pain and fevers. There is severe pancreatitis with necrosis of 60-70% of the gland including the head, uncinate process, and neck and body. There is a small amount of the tail enhancing normally. There is a large amount of retroperitoneal fluid around the pancreas and extending into the left anterior perirenal space along the colon down to the mid abdomen. There is moderate ascites most around the liver and on the right with small amount of ascites in the pelvis. The retroperitoneal fluid is poorly defined in most areas and thus does not yet represent a true pseudocyst. No gas collections or bowel obstruction or free intraperitoneal gas.