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[Gastrointestinal stromal tumors. Diagnosis, prognosis and current surgical treatment. Follow-up of 18 treated patients].

INTRODUCTION
Gastrointestinal stromal tumors (GIST) are the most frequent mesenchymal tumors of the digestive tract and their growth is directed through the signaling of the KIT or PDFGRA genes. The objective of the present study was to describe a series of cases of GIST tumors located in the stomach.


PATIENTS AND METHODS
We performed a retrospective, descriptive study of 18 patients diagnosed with gastric GIST and treated by means of gastric resection between July 1996 and June 2004. There were 12 women and six men, with a mean age of 63 years (range 33-84). In all patients, diagnosis was performed with immunohistochemical markers, such as CD34 and CD117. Investigations included endoscopy, abdominal ultrasonography, abdominal computerized axial tomography and fine-needle aspiration biopsy.


RESULTS
The main symptoms were digestive hemorrhage with severe anemia in 10 patients and abdominal pain in seven. In two patients, the tumors were incidental findings during laparotomy. Four patients underwent emergency surgery and the remainder underwent elective surgery. In all patients, gastric resection of variable extension was performed, according to tumoral location. Multicentric tumors were found in two patients. All patients were CD117- and CD34-positive. There were few postoperative complications. One patient died from acute myocardial infarction (5.6%). The mean follow-up was 47.5 months (range, 12-106). One patent died due to spread of a pancreatic neoplasm and the remaining patients are alive and without tumoral recurrence (94.1%).


CONCLUSIONS
Initial symptoms consist of upper gastrointestinal hemorrhage and abdominal pain. Gastroscopy and imaging techniques lead to a suspected diagnosis, which can be confirmed by immunohistochemical studies, in which the "gold standard" is positivity for CD117; CD34 (+), vimentin (+), actin (-) and protein S-100 (-) are also used. Treatment consists of tumoral resection with negative margins.