Parachordoma of the gastric serosa: report of a myxoid mimicry in an unusual location.

The authors report a case of an incidentally discovered myxoid stromal tumor occurring in the outer wall of the stomach of a 65-year-old woman. The tumor was phenotypically consistent with parachordoma (or myoepithelioma), showing a chordoid microscopic appearance of tumor cells loosely arranged within a myxoid or hyaline background. Immunoreactivity for high-molecular-weight keratins, S100 protein, and vimentin was detected. In this report, the authors address the differential diagnosis of parachordoma and the unusual location of this neoplasm.