Differential features of pancreatobiliary- and intestinal-type ampullary carcinomas at MR imaging.
OBJECTIVE
To define the differential imaging features of pancreatobiliary- and intestinal-type ampullary carcinomas at magnetic resonance (MR) imaging and to correlate these features with pathologic findings.


METHODS
This retrospective study was approved by the institutional review board; informed consent was waived. Fifty patients with surgically confirmed ampullary carcinoma and preoperative MR results were included. Two radiologists, blinded to histologic type of cancer, evaluated imaging findings in consensus. Univariate and multiple logistic regression analysis were performed to define imaging findings that were useful for differentiation of the two types of carcinomas.


RESULTS
On the basis of hematoxylin-eosin and immunohistochemical staining, 35 patients were classified as having pancreatobiliary type; and 15 patients, intestinal type. At MR, all of 15 intestinal carcinomas were nodular, whereas 16 (46%) of 35 pancreatobiliary carcinomas were infiltrative. Intestinal carcinomas were isointense (13 [87%] of 15) to hyperintense (two [13%] of 15), whereas 34% (12 of 35) of pancreatobiliary carcinomas manifested as hypointense compared with the duodenum on T2-weighted MR images (P = .034). Intestinal carcinoma commonly manifested with an oval filling defect at the distal end of the bile duct on MR cholangiopancreatographic (MRCP) images (11 [73%] of 15 vs four [11%] of 35 in pancreatobiliary type) (P < .001). At endoscopy, intestinal carcinoma manifested with an extramural protruding mass (n = 15, 100%) with a papillary surface (n = 11, 73%), whereas pancreatobiliary carcinoma manifested with intramural protruding (n = 5, 28%) or ulcerating (n = 1, 6%) gross morphologic features (P = .047) with a nonpapillary surface (n = 17, 94%) (P < .001). Multiple logistic regression analysis showed that an oval filling defect at the distal end of the bile duct was the only independent finding for differentiating intestinal from pancreatobiliary carcinoma (P = .027).


CONCLUSIONS
An oval filling defect at the distal end of the bile duct on MRCP images and an extramural protruding appearance with a papillary surface at endoscopy are likely to suggest intestinal ampullary carcinoma.
Chung
Yong Eun
YE
Department of Radiology, Institute of Gastroenterology, Research Institute of Radiological Science, Severance Hospital, Yonsei University College of Medicine, Seodaemun-ku, Shinchon-dong 134, Seoul 120-752, South Korea.
Kim
Myeong-Jin
MJ
Park
Mi-Suk
MS
Choi
Jin Young
JY
Kim
Hoguen
H
Kim
Sang Kyum
SK
Lee
Myungsu
M
Kim
Hee Jin
HJ
Choi
Jin-Sub
JS
Song
Si Young
SY
Kim
Ki Whang
KW
D000328:Adult; D000368:Aged; D014670:Ampulla of Vater / Q000473:pathology*; D001653:Bile Ducts, Intrahepatic / Q000473:pathology*; D016009:Chi-Square Distribution; D049448:Cholangiopancreatography, Magnetic Resonance / Q000379:methods*; D003138:Common Bile Duct Neoplasms / Q000175:diagnosis* / Q000473:pathology; D003937:Diagnosis, Differential; D004379:Duodenal Neoplasms / Q000175:diagnosis* / Q000473:pathology; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D007150:Immunohistochemistry; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D010190:Pancreatic Neoplasms / Q000175:diagnosis* / Q000473:pathology; D011379:Prognosis; D012189:Retrospective Studies; D015996:Survival Rate