Pancreatic cancer: Correlation of MR findings, clinical features, and tumor grade

Abstract

Purpose:To assess the frequency of occurrence of poorlymarginated and focally-defined pancreatic ductal adenocarcinoma by MRI and to determine whether these appearances correlate with clinical features and histopathological grade. Materials and Methods:Institutional review board with waiver of informed consent was obtained for this HIPAA compliant study. A total of 33 patients (16 female, 17 male, mean age ϭ 63.5 Ϯ 12.8, ranging from 41 to 80 years) with histopathologically-proven pancreatic ductal adenocarcinoma who underwent MR examination between August 2000 and February 2005 were retrospectively evaluated. Clinical data and histopathological tumoral grade were obtained from clinical charts; nine of 33 patients were excluded of the histopathological evaluation since their diagnosis was performed by fine needle aspiration biopsy and it was not possible to obtain the histopathological grade. Two radiologists reviewed all cases independently to identify whether cancers were poorly-marginated or focally-defined. Agreement between radiologists was assessed using the kappa coefficient. The overall correlation between imaging findings, clinical features, and histopathological grade was assessed with contingency tables using the Fisher's exact test. Results:Of the 33 patients, nine (27.2%) were classified as poorly-marginated and 24 (72.8%) as focally-defined. Agreement between the two reviewers was excellent (k ϭ 0.92, 95% confidence interval (CI) ϭ 0.78 -1.0). Poorly-marginated cancers exhibited well-to moderately-differentiated histopathology in 71.4% of cases, while focally-defined cancers had well-to moderately-differentiated histopathology in 17.6% of cases, P ϭ 0.02. Conclusion:A poorly-marginated appearance of pancreatic ductal carcinoma on MRI is not uncommon. These cancers exhibited statistically significant moderate-to well-differentiated histopathology compared to focally-defined cancers.

Pancreatic diffusion‐weighted imaging (DWI): Comparison between mass‐forming focal pancreatitis (FP), pancreatic cancer (PC), and normal pancreas

“…This is explained with variable histopathologic composition of PC. PC may have fibrosis, necrosis, and increased cellularity, which may affect its imaging features (12). Lower ADC values are explained with the presence of fibrosis (desmoplasia), which is the most characteristic feature of PC, and might be associated with restricted motion of the water protons (8).…”

“…Comparing the ADC values of malignant pancreatic mass to the remaining pancreas may be misleading since the remaining pancreas may reveal obstructive pancreatitis with different grades of severity, which may affect the ADC difference between the mass and the remaining pancreas. On the other hand, during the early stages of PC, the remaining pancreas may be unaffected or tumor may occur in the setting of chronic pancreatitis (11, 12). In cases of mass‐forming FP, however, most of the masses have indistinguishable ADC values as compared to the remaining pancreas.…”

Magnetic Resonance Imaging of Adenocarcinoma of the Pancreas

“…14 This appearance is commonly observed in pancreatic cancer that has been treated with chemotherapy and radiation therapy but may also be seen at initial presentation up to 27% of patients and has a significant association with well to moderately differentiated histologic pattern. 14 Pancreatic cancer involving the head region can cause stenosis of both the common bile duct and the main pancreatic duct with upstream ductal dilatation. On MRCP study, this feature results in the double duct sign, which was originally described on endoscopic retrograde cholangiopancreatography (Fig.…”

Differentiation between pancreatic carcinoma and mass‐forming chronic pancreatitis: Usefulness of high b value diffusion‐weighted imaging

“…Many diagnostic methods have been used for the differential diagnosis of pancreatic carcinoma and MFCP 8–17 . Carbohydrate antigen 19‐9 (CA 19‐9) is the most commonly used serological marker for screening and monitoring pancreatic carcinomas 11 .…”

“…Many diagnostic methods have been used for the differential diagnosis of pancreatic carcinoma and MFCP. [8][9][10][11][12][13][14][15][16][17] Carbohydrate antigen is the most commonly used serological marker for screening and monitoring pancreatic carcinomas. 11 However, CA 19-9 may be false-negative in the early course of pancreatic carcinoma and may be elevated in a variety of benign (e.g., pancreatitis, cholangitis, cirrhosis) and other malignant conditions (e.g., gastrointestinal cancers, cholangiocarcinoma, hepatocellular cancer).…”