The paper reviews the data available in the literature and describes the authors' observation of solid pseudopapillary tumor of the pancreas in a 33-year-old woman. Microscopically, the tumor, 2.5 x 2.5 x 2 cm in size, appeared predominantly as solid areas and solitary pseudopapillae comprising monomorphic round and oval cells with a light cytoplasm and round nuclei. Immunohistochemical study revealed diffuse cytoplasmic tumor cell staining in response to vimentin, alpha-antitrypsin, neuronspecific enolase, and cytokeratin 18; focal expression of synaptophysin and CD117; a negative reaction with antibodies to epithelial membrane antigen, S-100 protein, cytokeratins 7, 8, and 19, and CD57. Progesterone receptors were detectable in the nuclei of solitary tumor cells and the reaction with estrogen receptor was negative. The proliferation index (by Ki67) is about 0.2%.