Abstract

Gastrointestinal stromal tumors (GIST) are the most common mesenchymal neoplasms affecting the gastrointestinal tract. The main sites for GIST are the stomach and small intestine but they can also occur in the rectum, albeit rarely. We report a 58-year-old woman who presented with hematochezia. Endoscopically, a submucosal tumor with mucosal ulceration was located approximately 2 cm from the anal verge. The pelvic CT and MRI scanning findings demonstrated a large low-density lesion with intraluminal growth from the lower rectum and an absence of tumor infiltrations to other organs. The patient underwent an abdominoperineal resection of the rectum. A histopathological examination showed fascicular proliferation of spindle shaped cells. The mitotic rate was more than 30 mitotic figures per 50 high-power fields. A immunohistochemical examination revealed most of the tumor cells to be positive for the c-kit protein, CD34 and SMA (α-smooth muscle action). The tumor was diagnosed as a GIST of the rectum. (Korean J Gastrointest Endosc 2006;33:110⁣115)

• Keywords: Gastrointestinal stromal tumor (GIST), Rectum, Hematochezia