Is (18)F-fluorodeoxyglucose positron emission tomography meaningful for estimating the efficacy of corticosteroid therapy in patients with autoimmune pancreatitis?
BACKGROUND
Autoimmune pancreatitis (AIP) is often misdiagnosed as pancreatic cancer (PC). Both conditions accumulate (18)F-fluorodeoxyglucose (FDG), so FDG positron emission tomography (FDG-PET) is not discriminatory. This study aimed to evaluate the pattern of FDG accumulation, and the change in FDG uptake after steroid treatment in AIP and PC.


METHODS
We compared FDG-PET patterns between 18 patients with AIP and 20 patients with PC, and also evaluated the short-term changes in FDG uptake after steroid therapy.


RESULTS
FDG uptake was observed in 88.9% in AIP and 90.0% in PC. FDG uptake in extra-abdominal lymph nodes was seen more frequently in AIP, and uptake in salivary glands, eyes and biliary ducts was seen only in AIP. Follow-up PET was performed in 6 AIP patients and in 3 PC patients. Changes in SUV(max) after steroid therapy were estimated within 1 week in 5 AIP patients and in all 3 PC patients, retrospectively. In 4 AIP patients, the change in SUV(max) was more than 10%. On the other hand, in PC, SUV(max) increased or remained almost unchanged (within 10%).


CONCLUSIONS
FDG-PET pattern at baseline, and a decrease in FDG uptake after a short steroid trial can be useful for discriminating AIP from PC.
Shigekawa
Minoru
M
Department of Gastroenterology, Aichi Cancer Center Hospital, Nagoya, Japan. m-shigekawa@gh.med.osaka-u.ac.jp
Yamao
Kenji
K
Sawaki
Akira
A
Hara
Kazuo
K
Takagi
Tadayuki
T
Bhatia
Vikram
V
Nishio
Masami
M
Tamaki
Tsuneo
T
El-Amin
Hussein
H
Sayed
Zain El-Abdeen Ahmed
Zel-A
Mizuno
Nobumasa
N
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001327:Autoimmune Diseases / Q000000981:diagnostic imaging* / Q000188:drug therapy*; D003937:Diagnosis, Differential; D005260:Female; D019788:Fluorodeoxyglucose F18; D005938:Glucocorticoids / Q000008:administration & dosage*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010190:Pancreatic Neoplasms / Q000000981:diagnostic imaging*; D010195:Pancreatitis / Q000000981:diagnostic imaging* / Q000188:drug therapy*; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome
D005938:Glucocorticoids; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18