Abdominal extrapancreatic lesions associated with autoimmune pancreatitis: radiological findings and changes after therapy.
OBJECTIVE
To evaluate imaging findings of abdominal extrapancreatic lesions associated with autoimmune pancreatitis (AIP) and changes after steroid therapy.


METHODS
This study included nine AIP patients with abdominal extrapancreatic lesions, which were determined by retrospective radiological review. CT (initial and follow-up, n=9) and MR imaging (initial, n=5) were reviewed by two radiologists in consensus to determine imaging characteristics (i.e., size, number, attenuation or signal intensity, and contrast enhancement of the lesions, and the presence of overlying capsule retraction) and evaluate changes with steroid therapy of abdominal extrapancreatic lesions associated with AIP.


RESULTS
The most common abdominal extrapancreatic lesion associated with AIP was retroperitoneal fibrosis (RPF) in six patients. In five patients, CT and MR imaging revealed single or multiple, round- or wedge-shaped, hypoattenuating or hypointense, enhancing lesions in the renal cortex or pelvis. Other lesions included a geographic, ill-defined, hypoattenuating lesion with or without overlying capsule retraction in the liver in two and bile duct dilatation with or without bile duct wall thickening in four. Over a follow-up period of 6-81 months, CT exams of eight patients demonstrated partial or complete improvement of the abdominal extrapancreatic lesions, albeit their improvement in general lagged behind that of the pancreatic lesion.


CONCLUSIONS
On CT or MR imaging, the abdominal extrapancreatic lesions associated with AIP are various in the retroperitoneum, liver, kidneys and bile ducts, and are reversible with steroid therapy.
Sohn
Jeong-Hee
JH
Department of Radiology & Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, 388-1 Pungnap2-dong, Songpa-gu, Seoul 138-736, Republic of Korea.
Byun
Jae Ho
JH
Yoon
Seong Eon
SE
Choi
Eugene K
EK
Park
Seong Ho
SH
Kim
Myung-Hwan
MH
Lee
Moon-Gyu
MG
D000005:Abdomen / Q000473:pathology*; D000368:Aged; D001327:Autoimmune Diseases / Q000175:diagnosis*; D005260:Female; D005355:Fibrosis / Q000175:diagnosis* / Q000517:prevention & control*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010195:Pancreatitis / Q000175:diagnosis* / Q000188:drug therapy*; D011860:Radiography, Abdominal / Q000379:methods*; D012189:Retrospective Studies; D013256:Steroids / Q000627:therapeutic use*; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome
D013256:Steroids