Gastrointestinal Stromal Tumors with Unusual Localization: Report of Three Cases with a Brief Literature Review.

The most common tumors derived from the mesenchyme of the gastrointestinal system are stromal tumors. These tumors are typically seen in the stomach and small intestine and less frequently in the colon, rectum and esophagus and are very rarely located outside the gastrointestinal system. Cure is provided with complete surgical resection with resection borders free of tumor. Tumor size, mitotic index, localization, CD117 and CD34 negativity in immunohistochemical studies, mucosal ulceration and presence of necrosis help to predict recurrence of the illness and patient survival. In high-risk gastrointestinal stromal tumors (GISTs) there is an increased rate of recurrence and shortened survival despite complete surgical resection. Thus patients with a high-risk GIST should be given adjuvant therapy with imatinib mesylate. Sunitinib maleate is another FDA-approved agent only for cases who cannot tolerate imatinib or who are resistant to it. Herein we present three cases with GISTs in different locations of the gastrointestinal system with a review of the relevant literature.