Long-term surgical outcomes of patients with type 1 autoimmune pancreatitis

Although pancreatectomy has sometimes been performed for patients with autoimmune pancreatitis (AIP) presenting atypical radiologic findings under the diagnosis of pancreatobiliary malignancy, the long-term surgical outcome of these patients had not yet been fully elucidated.

The long-term surgical outcomes of 13 patients with pathologically diagnosed type 1 AIP with immunohistochemical staining for immunoglobulin G4 (IgG4) were retrospectively compared with those of 34 patients with conventional chronic pancreatitis to evaluate the residual pancreatic function.

A definite relapse of AIP in terms of the clinical manifestations and diagnostic imaging was not found in any of the patients, although one patient experienced an attack of acute pancreatitis caused by pancreatic stones, and stricture of the hepaticojejunostomy occurred in one patient. The overall body weight decreased significantly more in patients with AIP than in patients with conventional chronic pancreatitis (p < 0.05); however, there was no difference in the preoperative nondiabetic patients. Refractory diarrhea occurred in only one patient with AIP. The cumulative new-onset rates of diabetes mellitus of the ten patients with AIP and 24 patients with conventional chronic pancreatitis at 5 years after the surgery were 32.5 and 26.1 %, respectively (p = 0.70).

Careful long-term follow-up is needed for patients undergoing pancreatectomy for type 1 AIP because remnant pancreatic function can deteriorate as severely as that of patients who undergo pancreatectomy for conventional chronic pancreatitis. In the present series, however, there were few definite manifestations indicating relapse or the persistent existence of AIP.