Case ReportCase report of diffusely metastatic rectal GIST

•Rectal gastrointestinal tumors (GISTs) are rare mesenchymal tumors.•Rectal GISTs are extremely rare and account for approximately 2% of all GIST tumors.•Majority of GISTs have a benign course.•Treatment with imatinib mesylate should be arranged as soon as possible.•The most common cause of death after resection of a rectal GIST is distant metastasis.

This is a case report of an aggressive, diffusely disseminated Stage IV rectal gastrointestinal stromal tumor (GIST) in a 57-year-old male that presented for symptoms of malaise, constipation, and twenty pound weight loss in 2 months. Upon rectal examination, a hard 4 centimeter submucosal mass was found at the 9-12 o'clock position. Liver and lung metastases were visualized on computerized tomography (CT) of the chest, abdomen, and pelvis on metastatic work-up. He was deemed a poor surgical candidate due to diffuse metastatic disease and referred for palliative chemotherapy. The patient had suffered a perforation of his rectal wall two weeks after his initial presentation and passed away shortly thereafter. He never received palliative chemotherapy. We present a case report as a unique case of an extremely aggressive and quickly fatal GIST tumor.