A Spindle Cell Predominant Pancreatic Solid-pseudopapillary Tumor

A hitherto unrecognized variant of solid-pseudopapillary tumor (SPT) of the pancreas is reported. The tumor presented in the pancreatic tail of a 44-year-old female patient. It was a well-defined, solid nodule measuring 25 mm in diameter, with homogenous tan gray cut surface. Histologically, the neoplasm was mostly composed of sheets of spindle cells. No cellular atypia and mitosis was identified. The periphery of the tumor showed typical feature of SPT. Immunohistochemically, the tumor cells were positive for vimentin, CD10, CD56, beta-catenin, and alpha1-antichymotrypsin, but negative for cytokeratin, chromogranin, synaptophysin and S-100 protein. Ultrastructurally, the tumor showed a few acinar spaces with microvilli between tumor cells. This case is peculiar in that the tumor did not show gross cystic change and predominantly consists of spindle shaped tumor cells, so may cause difficult diagnostic problem.