Abstract: Objective To investigate the imaging signs of CT and MRI for pediatric solid pseudopapillary tumor (SPTP) of the pancreas. Methods This study retrospectively reviewed 21 cases of SPTP confirmed by clinic surgery and pathology. Results Among the 21 cases, there were two males and 19 females. The median age was 11 years. Preoperative CT scan was performed in 19 patients, and preoperative MRI scan was performed in 7 patients. All the 21 cases were of single lesion and often occurred in the body/tail of pancreas, with a mean diameter of 5.80(5.00~7.31) cm. All tumors were cystic and solid masses. Nine cases were mainly composed of solid tissue. The other two cases mainly had cystic components. Ten cases were composed of cystic and solid tissue, and the proportion of cystic components was close to solid components. On precontrast CT scan, SPTPs were typically well demarcated, and equal/low density lesions comprising both solid and cystic components. MRI showed that the solid components of the tumor showed low signal in T 1 WI and slightly higher signal in T 2 WI, hemorrhage was showed high signal in T 1 WI. The solid portion was mild to obviously enhanced slightly in the arterial phase, with an enhancement degree lower than normal pancreas, and progressive enhancement in the portal venous phase. In this group, five cases were confirmed to be malignant SPTP by surgery and pathology, with all the lengths greater than 5 cm and incomplete capsule, among which 3 cases were lobulated, and 2 cases had mass calcification. Conclusion The characteristic imaging signs of CT and MRI for pediatric solid SPTP have significant value in the diagnosis correctly and evaluation the malignant risk of tumor before surgery

Key words: solid pseudopapillary tumor of the pancreas; X-ray computed tomography; magnetic resonance imaging; child