A Case of a Pedunculated Exoluminal Gastrointestinal Stromal Tumor in the Stomach

A 49-year-old man visited our hospital with a complaint of a left lower quadrant abdominal mass. Abdominal computed tomography (CT) showed an exophytic tumor attached to the stomach; the marginal region was intensely enhanced as seen on contrast imaging in the delayed phase. The gastric tumor was excised using a laparoscopic procedure. The gastric tumor was removed along with the gastric wall where the tumor was attached to by a pedicle. The external surface of the tumor showed a well-encapsulated appearance and several engorged vessels. Histologically, the tumor cells had a clear or eosinophilic cytoplasm and round nuclei. Four mitotic figures were seen per 50 cells on a high power field. Immunohistochemical staining demonstrated positive expression of c-kit, CD34, and vimentin and negative expression of smooth muscle actin (SMA) and S-100. The final diagnosis was a pedunculated exoluminal gastrointestinal stromal tumor (GIST). (Korean J Gastrointest Endosc 2007;35:332-336)