Spontaneous remission of autoimmune pancreatitis: Four case reports

Autoimmune pancreatitis (AIP) is a particular type of chronic pancreatitis, and steroid treatment of AIP is effective. Spontaneous remission (SR) of AIP without steroids is relatively rare. The international consensus for the treatment of autoimmune pancreatitis suggests that patients with AIP with obstructive jaundice, abdominal pain, and back pain related to the pancreas or the bile duct should be treated with steroids; most asymptomatic patients with AIP may improve without steroids. However, in our clinical work, we found that the clinical characteristics of AIP patients with SR vary. Four of these cases are described here. In addition, to our knowledge, there is no previously published report of dynamic imaging before and after SR of AIP at present.

We present the cases of four patients with AIP (two females and two males) in which the AIP improved spontaneously without steroid treatment. Two patients were asymptomatic, one patient had abdominal pain with obstructive jaundice, and one patient had intermittent right upper abdominal pain. Three patients presented with localized pancreatic enlargement and one with diffuse pancreatic enlargement. In addition to the pancreatic lesions, bile duct involvement was seen in two patients, and no extra-pancreatic organ involvement was found in the other two patients. The serum IgG4 level of all patients was more than twice the normal level. After SR in the four patients, the affected pancreases exhibited three types of image features: Return to normal, progressive fibrosis, and atrophy and calcification.

The clinical features of SR in our four patients with AIP differ, but the imaging findings share some characteristics. After SR, in some cases the affected pancreas could return to normal, although some patients suffer from progressive fibrosis and atrophy as well as calcification.