Imaging features of solid pseudopapillary tumor of the pancreas on multi-detector row computed tomography

AIM:To retrospectively analyze the imaging features of solid-pseudopapillary tumors(SPTs) of the pancreas on multi-detector row computed tomography(MDCT) and define the imaging findings suggestive of malignant potential.METHODS:A total of 24 consecutive cases with surgically and pathologically confirmed SPTs of the pancreas underwent preoperative abdominal MDCT studies in our hospital.All axial CT images,CT angiographic images,and coronally and sagittally reformed images were obtained.The images were retrospectively reviewed at interactive picture archiving and communication system workstations.RESULTS:Of the 24 cases of SPTs,11 cases(45.8%) occurred in the pancreatic head and seven(29.1%) in the tail.Eighteen were pathologically diagnosed as benign and six as malignant.MDCT diagnosis of SPTs was well correlated with the surgical and pathological results(Kappa = 0.6,P < 0.05).The size of SPTs ranged from 3 to 15 cm(mean,5.8 cm).When the size of the tumor was greater than 6 cm(including 6 cm),the possibilities of vascular(8 vs 1) and capsular invasion(9 vs 0) increased significantly(P < 0.05).Two pathologically benign cases with vascular invasion and disrupted capsule on MDCT presented with local recurrence and hepatic metastases during follow-up about 1 year after the resection of the primary tumors.CONCLUSION:Vascular and capsular invasion with superimposed spread into the adjacent pancreatic parenchyma and nearby structures in SPTs of the pancreas can be accurately revealed by MDCT preoperatively.These imaging findings are predictive of the malignant potential associated with the aggressive behavior of the tumor,even in the pathologically benign cases.