Gastrointestinal stromal tumors of the rectum: Clinical, pathologic, immunohistochemical characteristics and prognostic analysis.

Objective. To describe the clinical, pathological and immunohistochemical characteristics of rectal gastrointestinal stromal tumors (GISTs) and to correlate them with clinical outcomes. Material and methods. A retrospective review of 29 patients with surgically treated rectal GISTs during the period from 1997 to 2005 was undertaken. The NIH (National Institute of Health Consensus) criteria were applied. Results. All the rectal GISTs in our series originated in the lower half of the rectum and patients underwent primary surgery for complete resections; High-risk, intermediate-risk, low-risk and very low-risk GISTs were found in 11, 6, 5 and 7 patients, respectively. Necrosis, adjacent (mucosal or serosa) invasion and marked pleomorphisms were found in 10, 7 and 20 patients, respectively. Positive expression of CD117, CD34, SMA and S-100 was found in 28, 28, 7 and 3 patients, respectively. Twelve patients had recurrence or metastasis within the median disease-free survival time of 41 months. Among the patie...