A 67-year-old, previously fit, woman presented with a history of rectal bleeding. Per rectum examination revealed a low rectal mass, which on endoscopy was demonstrated to be submucosal. MR rectum confirmed a 5 cm rectal mass displacing the rectum anteriorly. Chest x-ray and abdominal CT did not reveal any metastatic disease. Biopsies were consistent with high grade gastrointestinal stromal cell tumour (GIST,) C-Kit was positive and Ki67 greater>20%. The patient came forward for an abdominoperineal rectal resection with permanent stoma and had an uncomplicated postoperative course.GISTs are rare tumours that develop from interstitial cells of Cajal. Only 5% of GIST tumours arise in the rectum and GIST should be considered as differential diagnosis for submucous rectal lesions. Complete resection is recommended to achieve local disease control either by local resection or rectal resection depending on size. The benefit of imatinib as neoadjuvant treatment is uncertain.Figure 1a & b: MR rectum showing a posteriorly located rectal GIST and the subsequent operation specimen.

A 67-year-old, previously fit, woman presented with a history of rectal bleeding. Per rectum examination revealed a low rectal mass, which on endoscopy was demonstrated to be submucosal. MR rectum confirmed a 5 cm rectal mass displacing the rectum anteriorly. Chest x-ray and abdominal CT did not reveal any metastatic disease. Biopsies were consistent with high grade gastrointestinal stromal cell tumour (GIST,) C-Kit was positive and Ki67 greater>20%. The patient came forward for an abdominoperineal rectal resection with permanent stoma and had an uncomplicated postoperative course.GISTs are rare tumours that develop from interstitial cells of Cajal. Only 5% of GIST tumours arise in the rectum and GIST should be considered as differential diagnosis for submucous rectal lesions. Complete resection is recommended to achieve local disease control either by local resection or rectal resection depending on size. The benefit of imatinib as neoadjuvant treatment is uncertain.Figure 1a & b: MR rectum showing a posteriorly located rectal GIST and the subsequent operation specimen.