Pancreatic main-duct involvement in branch-duct IPMNs: an underestimated risk.
OBJECTIVE
This study aimed to analyze a large single-center population of resected intraductal papillary mucinous neoplasms (IPMN) of the pancreas with respect to risk factors of malignant transformation.


BACKGROUND
There is international consensus that main-duct (MD) as well as mixed-type IPMNs should be treated surgically due to a high risk of malignancy. In contrast, there is an ongoing controversy about surgery of branch-duct type IPMN (BD-IPMN).


METHODS
All consecutive patients who underwent surgery for IPMN between January 2004 and December 2012 were included. Clinical characteristics and preoperative imaging were correlated with histopathological features.


RESULTS
A total of 512 patients underwent pancreatic surgery and had a histological proof of IPMN. According to preoperative imaging, 74 patients had MD-IPMN (14%), 205 mixed-type (40%), and 233 suspected BD-IPMN (46%). On histopathology, 162 of 512 patients revealed low-grade, 105 moderate, and 52 high-grade dysplasia. One hundred ninety-three IPMN patients (38%) suffered from invasive carcinoma. Among invasive IPMNs, the majority (58%) were mixed-type lesions according to preoperative imaging. Of 141 Sendai negative BD-IPMNs, a malignancy rate of 18% (high-grade dysplasia and invasive carcinoma) was found. Most interesting, 29% of suspected BD-IPMNs (67/233) revealed histological involvement of the main pancreatic duct not evident in preoperative imaging.


CONCLUSIONS
All subtypes of IPMNs display a relevant risk for malignant transformation. By abdominal imaging, many IPMNs are misclassified as BD-IPMNs but reveal mixed-type lesions in histopathology. Because currently available preoperative diagnostics are not sufficient to reliably diagnose BD-IPMNs, surgical resection for suspected small branch-duct IPMN should be considered in patients fit for surgery.
*Department of General, Visceral and Transplantation Surgery †Department of Diagnostic and Interventional Radiology ‡Institute of Pathology, University of Heidelberg, Im Neuenheimer Feld 110, 69120 Heidelberg, Germany.
Stefan
S
Fritz
Miriam
M
Klauss
Frank
F
Bergmann
Oliver
O
Strobel
Lutz
L
Schneider
Jens
J
Werner
Thilo
T
Hackert
Markus W
MW
Büchler
D002288:Adenocarcinoma, Mucinous / Q000175:diagnosis / Q000473:pathology / Q000601:surgery*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000097:blood; D021441:Carcinoma, Pancreatic Ductal / Q000175:diagnosis / Q000473:pathology / Q000601:surgery*; D002291:Carcinoma, Papillary / Q000175:diagnosis / Q000473:pathology / Q000601:surgery*; D003952:Diagnostic Imaging; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D009361:Neoplasm Invasiveness; D010183:Pancreatic Ducts / Q000473:pathology / Q000601:surgery*; D011446:Prospective Studies; D012307:Risk Factors; D016896:Treatment Outcome
D015415:Biomarkers