Renal cortical lesions in patients with autoimmune pancreatitis: a clue to differentiation from pancreatic malignancy.
OBJECTIVE
To describe the occurrence of renal cortical lesions (RCLs) in patients with autoimmune pancreatitis (AIP).


METHODS
This retrospective study was approved by our research ethics board; informed consent was waived. Systematic search of CT scan reports in 5-year interval yielded 17 patients with AIP (male:female; 11:6, age 18-80 years). A consecutive group of 22 patients with pancreatic adenocarcinoma was used as control (male:female; 10:12, age 42-76 years). The CT scans of the two groups were mixed and randomized. Two blinded radiologists independently reviewed the kidneys for the presence of wedge-shaped RCLs. Fisher's exact test was used to determine statistical significance. Consensus review of all imaging of positive patients with AIP and RCLs and three additional patients identified anecdotally was performed.


RESULTS
Both readers independently identified the same 6/17 (35%) patients in the study group and 0/22 in the control group with two or more RCLs. This difference was statistically significant (p=0.004). The sensitivity, specificity, positive and negative predictive values of RCLs in the differentiation of AIP from pancreatic adenocarcinoma were 35%, 100%, 100%, and 67%, respectively. To the six AIP patients with RCLs, we added three more identified anecdotally. In 7/9, >5 RCLs were seen which were wedge-shaped and cortical-based, ranging from <1 to 4cm. Typical pancreatic findings of AIP were noted in all, with the gland affected focally in 5/9 patients.


CONCLUSIONS
We have shown the presence of multiple renal cortical lesions which occur in approximately 35% of our AIP patient population.
Khalili
Korosh
K
Department of Medical Imaging, University Health Network and Mount Sinai Hospital, Room 3-961, 610 University Avenue, Toronto, Ontario M5G 2M9, Canada. Electronic address: Korosh.Khalili@uhn.on.ca.
Doyle
Deirdre J
DJ
Department of Medical Imaging, University Health Network and Mount Sinai Hospital, Room 3-961, 610 University Avenue, Toronto, Ontario M5G 2M9, Canada.
Chawla
Tanya P
TP
Department of Medical Imaging, University Health Network and Mount Sinai Hospital, Room 3-961, 610 University Avenue, Toronto, Ontario M5G 2M9, Canada.
Hanbidge
Anthony E
AE
Department of Medical Imaging, University Health Network and Mount Sinai Hospital, Room 3-961, 610 University Avenue, Toronto, Ontario M5G 2M9, Canada.
D000328:Adult; D000368:Aged; D001327:Autoimmune Diseases / Q000150:complications*; D016022:Case-Control Studies; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D007674:Kidney Diseases / Q000000981:diagnostic imaging* / Q000453:epidemiology / Q000209:etiology*; D008297:Male; D008875:Middle Aged; D010195:Pancreatitis / Q000150:complications*; D011237:Predictive Value of Tests; D015995:Prevalence; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed