Gastrointestinal stromal tumors: a demographic, morphologic and immunohistochemical study.

BACKGROUND AND AIM: There is limited published information on gastrointestinal stromal tumors (GIST) in the South Asian region. This study was conducted to describe the demographic characteristics, organ distribution and frequency of risk categories in cases of GIST referred to a tertiary hospital. METHODS: Data pertaining to 37 cases of gastrointestinal stromal tumors received at the histopathology section of the Aga Khan University Hospital between December 2004 and July 2005 were analyzed. Immunohistochemical stains including vimentin, CD34, CD117 (c-kit), ASMA, desmin and S-100 were performed. RESULTS: Of 37 tumors, 24 (64.9%) were from males. The mean age of the patients was 50.0 years (95% CI 45.3-54.6). Tumors were categorized as high risk (27 cases; 69.2%), intermediate risk (4 cases; 10.3%) and low risk (3 cases; 7.7%). The most common site of involvement was the stomach (29.7%), followed by small bowel (24.3%), mesentery (10.8%), pancreas (8.1%), rectum (2.7%) and retroperitoneum (2.7%). In 21.6% of cases, the site of origin was not specified. The mean age at diagnosis was 50.9 years (95% CI 45.5 - 56.3) in the high risk and 44.8 years (95% CI 28.6 - 60.9) in the intermediate risk category. CONCLUSIONS: Cases of GIST referred to us were more frequently from men, most commonly from stomach or small bowel, mostly in the high risk category, and presented a decade earlier than in other reported series.