Colorectal gastrointestinal mesenchymal tumours. Report of a stromal case of the rectum (GIST) and a leiomyosarcoma of the transverse colon.

BACKGROUND: Gastrointestinal stromal tumours (GISTs) are the most common mesenchymal tumours of the gastrointestinal tract. They are positive to C-kit (CD 117), more common in the older males, and mostly in the stomach, less in the colon and rectum and oesophagus. Benign tumours are more common than the malignant ones. Classification of GISTs is based on morphology and immunochemistry. METHODS: We report two cases of colorectal gastrointestinal mesenchymal tumours, one on the transverse colon which was found to be immunohistochemically leiomyosarcoma and the other on the rectum which met the GIST criteria. The patients underwent transversectomy and abdominal perineal resection, respectively. CONCLUSIONS: They did not receive Imanitib postoperatively and two years after there is no evidence of recurrence. Surgery is the treatment of choice for resectable GISTs, and other mesenchymal tumours benign or malignant.