Imaging and pathologic characteristics of solid pseudopapillary tumor of pancreas

Objective: The imaging characteristics of solid pseudopapillary tumor of pancreas (SPTP) by color ultrasound, CT, MRI and endoscopic ultrasonography (EUS) were analyzed and compared with pathological results to explore methods of early diagnosis of SPTP. Methods: The color ultrasound, CT, MRI and EUS of SPTP of 30 SPTP cases confirmed by surgery and pathology were retrospectively analyzed to determine the location, size, shape, density, signal, and enhancement pattern of the tumor. The patients underwent EUS puncture biopsy before the operation. The specimen after surgical resection were examined by pathology and compared with the pathology. Results: The SPTP ultrasound of patients showed hypoechoic solid masses. CT findings mainly manifested as mixed density of cystic and solid shadows, with some solid structures showed papillary or wall nodular protrusions, and strengthened after enhancement. MRI showed heterogeneous mixed signals on T1WI and T2WI. The specific signs such as necrotic cystic degeneration and hemorrhage inside the tumor can be identified, and the solid parts of the tumor were enhanced progressively. The patients' EUS examination mainly showed hypoechoic solid masses with uneven internal echo. The pathological diagnosis was confirmed by EUS biopsy before surgery, which was consistent with the postoperative pathological results. Conclusion: Solid pseudopapillary tumor of the pancreas has certain imaging characteristics, with its pathological diagnosis can be confirmed by EUS biopsy postoperatively.