Contrast-enhanced ultrasonography of small solid pseudopapillary tumors of the pancreas: enhancement pattern and pathologic correlation of 2 cases.

OBJECTIVE: The purpose of this series is to describe the value of contrast-enhanced ultrasonography (CEUS) in the characterization of small pseudopapillary tumors (SPTs) of the pancreas. METHODS: Two cases of SPTs found on conventional ultrasonography, both located at the pancreatic body, were studied with spiral computed tomography, magnetic resonance imaging, and CEUS. A final diagnosis was obtained with histologic analysis after distal pancreatectomy. Immunohistochemical analysis of the tumors with the CD34 antigen was performed. RESULTS: At CEUS, the 2 SPTs had a slight peripheral rim enhancement in the early dynamic phases. The presence of this enhancement pattern at CEUS, not clear at spiral computed tomography or at magnetic resonance imaging, suggested the diagnosis of SPTs with a peripheral pseudocapsule deriving from the compression of the pancreatic parenchyma. The presence of a perilesional pseudocapsule was proved at immunohistochemical analysis of the tumors with the CD34 antigen. CONCLUSIONS: Contrast-enhanced ultrasonography can improve the characterization of SPTs by showing the typical rim enhancement of these pancreatic tumors.