Solid Pseudopapillary Neoplasm of the Pancreas: A Rare Entity With Unique Features.

Solid pseudopapillary neoplasm of the pancreas is a rare entity with low malignant potential and excellent overall prognosis. It has nonspecific clinical presentations such as abdominal pain and nausea, with vague radiologic features. Histologic features of this neoplasm are usually specific. The tumor shows minimally cohesive, uniform, monotonous cells lining delicate capillary-sized blood vessels, described as pseudopapillary architecture. Other features including hyaline globules, cytoplasmic vacuoles, and nuclear grooving are frequently present. Use of a select panel of immunostains always helps pathologists to differentiate this tumor from other circumscribed tumors of the pancreas. Recently, β-catenin, CD10, and E-cadherin have been shown to be very important in the diagnosis of solid pseudopapillary neoplasm. Nuclear staining of tumor cells by β-catenin and membranous presentation of CD10 is seen in almost 100% of cases. Tumor cells can be partially positive for synaptophysin and chromogranin. This tumor has a low malignant potential, and definite treatment is surgical resection.