Extra-gastrointestinal stromal tumor of the greater omentum: report of a case and review of the literature.

BACKGROUND: Gastrointestinal stromal tumors (GISTs) represent the majority of primary non-epithelial neoplasms of the digestive tract, most frequently expressing the KIT protein detected by the immunohistochemical staining for the CD117 antigen. Extra-gastrointestinal stromal tumors (EGISTs) are neoplasms with overlapping immunohistological features, occurring in the abdomen outside the gastrointestinal tract with no connection to the gastric or intestinal wall. CASE PRESENTATION: We here report the clinical, macroscopic and immunohistological features of an EGIST arising in the greater omentum of a 74-year-old man, with a discussion on the clinical behavior and the prognostic factors of such lesions and a comparison with the gastrointestinal counterpart. CONCLUSION: The EGISTs in the greater omentum can grow slowly in the abdomen for a long time without clinical appearance. In most cases a preoperative diagnosis is not possible, and the patient undergoes a surgical operation for the generic diagnosis of "abdominal mass". During the intervention it is important to achieve a complete removal of the mass and to examine every possible adhesion with the gastrointestinal wall. Yamamoto's criteria based on the evaluation of the mitotic rate and the MIB-1 labelling index seems to be useful in predicting the risk for recurrence or metastasis. More studies are necessary to establish the prognostic factors related to localization and size of the EGIST and to evaluate the impact of the molecular characterization as an outcome parameter related to the molecular targeted therapy. In absence of these data, an accurate follow-up is recommended.

Gastrointestinal stromal tumours: an analysis based on personal experience.

We present our experience in the treatment of 18 patients affected by gastrointestinal stromal tumours (GIST) from January 1988 to march 2002. The ratio M.F was of 2:1 and the median age of 68.6 years. In 13 patients the tumours were located in the stomach while in 5 patients in the jejunum ileum area. In 7 patients the neoplasms were malignant. All the patients were operated and in 11 patients a partial gastric resection was carried out. 2 patients had a total gastrectomy and 5 had a small bowel resection. The diagnostic and therapeutic options and the uncertain prognosis of these neoplasms are discussed.