Unexpected diagnosis for a gastric polyp: Granular cell tumor: Case report and review of the literature.

A granular cell tumor (GCT) is a rare neoplasia that originates from Schwann cells. It usually appears in the skin or soft tissues, but it may occur anywhere in the body. The gastrointestinal tract is an unusual developmental site for a GCT, the esophagus being the most common site of origin for this tumor. The stomach is one of the most unique sites of origin for GCT, with less than 80 cases being mentioned in the literature. Histologically, GCTs consist of fusiform and polygonal cells, with granular cytoplasm, arranged in compact 'nests'. Immunohistochemically, these tumors show positivity for S100 protein, CD68, CD56 and, in a smaller percentage, they are positive for other antibodies, most notably inhibin alpha. We report the case of a 52-year-old woman with a solitary GCT that had developed in the gastric cardia, discovered on a routine gastroscopy and successfully treated by endoscopic submucosal dissection.