Exophytic gastrointestinal stromal tumor of the stomach. Report of two cases

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal neoplasms of the gastrointestinal tract. Most GISTs occur in the stomach (60-70%). Their diagnosis is established immunohistochemically and reveals that the tumor cells are immunoreactive for the antigens CD117 and CD34. The infiltration of the adjacent organs, the large tumor size (>5cm) and the mitosis count of the cells (>5/50 CHPFs) are typical characteristics of GIST malignancy. GISTs rarely infiltrate adjacent organs and usually push them back. The clinical behaviour of GISTs is highly variable and tumor size mitotic rate and location are prognostic determinants.The biologic behaviour of GIST is variable. The majority were previously thought to be benign due to their characteristically bland histopathologic features. However, it is becoming increasingly clear that with long follow-up, virtually all GISTs have the potential for malignant behaviour, even those 2 cm or less with bland histologic features. Thus, it is not appropriate to define any GIST as "benign" per se.We present two cases of exophytic gastric GIST which were recently treated successfully in our Clinic with “wedge” gastric resection. The margins were negative and there was neither rupture of the tumor, nor spillage.