To improve the current understanding on the imaging features of pancreatic schwannoma.

Clinical data of pancreatic schwannoma patients admitted in Changhai Hospital affiliated with Navy Medical University from January 1989 to January 2019 were retrospectively analyzed, related literature on pancreatic schwannomas was retrieved through the Chinese and English database, and clinical and imaging features of pancreatic schwannoma were analyzed.

A total of 84 cases were analyzed, including 3 cases of pancreatic schwannomas in Changhai hospital, and 81 cases reported in the literature. The age of onset was 17-78 years old, with an average of 55 years. There were 30 males and 54 females. The main symptoms were abdominal pain or the detection of pancreatic mass via body check. Pancreatic schwannoma was mainly in pancreatic head, and the lesion has a long diameter of 1-18 cm with an average of 4.6 cm, which can be solid, cystic (most frequent) and cystic-solid. The border of the lesion from the normal tissue was clear, and semi-transparent capsule composed of neural external membrane and fiber were often found. 15 patients underwent endoscopic ultrasonography guided fine needle aspiration, and diagnostic accuracy was 73.3%(11/15). No typical findings for pancreatic schwannoma was detected on CT. MRI was performed in 35 cases, and 12 cases had complete data. The characteristics of target sign were tumor tissue in completely low signal at T₁WI, and in partially low signal and partially high signal at T₂WI, and completely opposite signal characteristics of T₂WI area after T₁ enhancement, referring to the finding that low T₂WI signal part was gradually enhanced to be high signal, but high signal part was not enhanced and in low signal.

Pancreatic schwannoma is rare, and its target signs by MRI have imaging features which can help to improve the preoperative diagnosis.

Pancreas; Neurilemmoma; Tomography, X-ray computed; Magnetic resonance imaging