The imaging features of pancreas solid pseudopapillary tumor in children

Abstract

Objective To analyze the imaging features of solid pseudopapillary neoplasm of pancreas (SPN) in children, and to improve the awareness of the disease. Methods From January 2007 to December 2016, 12 patients with SPN proven pathologically were enrolled in the study, of whom 12 cases underwent CT scanning and 3 cases underwent MRI scanning. The imaging data of SPN were analyzed retrospectively. The tumor parameters included the location, size, shape, margin, capsule, form, inhancement degree, and presence of calcification, biliary obstruction, surrounding, ascites, lymph node metastasis, as well as distant metastasis, which were comparative analyzed with that of pathology. Results CT showed that 3 cases were located in the head of pancreas, 7 cases were located in the body/tail of pancreas, and 2 cases were ectopic. Twelve cases were circular tumors, the diameter of which ranged from 28—76 mm (median diameter 48 mm) . Capsules were showed in 10 cases, calcification was seen in 4 cases and hemorrhage was seen in 1 case. Three cases were solid, 8 cases were solid and cystic mixed, and 1 case was cystic. The tumors were heterogeneous, and the solid portion of SPN was moderately to obviously enhanced gradually whereas the cystic part remained unenhanced. Nine cases showed that the tumors growed to the outside of pancreas, in which 4 cases covered by the normal pancreas tissue, 1 case located inside of the pancreas. One case caused biliary obstruction and the collateral circulation of splenic arteriovenous was established in 2 cases due to tumor compressed. Ascites was seen in 2 cases. MRI showed that the cystic components of tumor in 3 cases showed low signal in T1WI and high signal in T2WI, with no enhancement. The solid components of the tumor showed equal signal in T1WI and slightly higher signal in T2WI, with obvious enhancement. Capsules were showed in 3 cases with low signal in T1WI and T2WI, which were obviously enhanced in 2 cases and without enhancement in 1 case; hemorrhage was showed high signal in T1WI in 1 case. No lymph node metastasis and distance metastasis were observed in 12 cases. Conclusions The characteristic imaging findings of SPN in children are boundary clear, capsules, calcification, circular pancreas tumors, which grow to the outside of pancreas, with varied degrees of hemorrhage and necrosis. The solid portion of SPN is moderately or obviously enhanced gradually. Key words: Pancreatic neoplasms; Tomography, X-ray computed; Magnetic resonance imaging; Child