Abstract

Gastrointestinal stromal tumors (GISTs) are mesenchymal tumors arising from the interstitial cells of Cajal. Originally thought to be leiomyosarcomas, these tumors are traditionally resistant to chemotherapy and radiation therapy. Molecular studies have identified the gene mutations that cause these masses to proliferate. The KIT proto-oncogene and PDGFRA mutations have been successfully implicated as the insults leading to disease. We present a 54 year old male, whose tumor was very aggressive yet multi-modality therapy did show an excellent response. Discovered incidentally while he was undergoing a sigmoid colostomy for benign disease, the patient had evidence of metastatic GIST disease. We utilized radiology, pathology and immunohistochemistry to provide a definitive diagnosis. Radiology was extremely useful in identifying disease and possible metastases. Furthermore the use of PET scans, particularly PET/CT allows clinicians to monitor and tailor therapy. Successful management of GISTs involves medical and surgical therapy. Imatinib mesylate is a drug used to inhibit the production of the KIT proto-oncogene. Coupled with surgery, this combination holds promise in successful management and possible eradication of the disease.

Key words: Gastrointestinal stromal tumor, PET scan, Imatinib, gene therapy, small bowel obstruction.