EUS based strategy for surgical resection of mesenchymal tumors (MTs) of upper gastrointestinal tract

Mesenchymal tumors of upper g.i. tract are often benign but, some of them, as GISTs or GANTs may have a malignant behaviour. Therefore a precise diagnosis would be important for their management and surgical treatment, if needed; but it is very difficult to achieve preoperatively. The aim of the study was to verify if a more detaliled classification of MTs, based on EUS imaging, could improve therapeutic planning. From 2000 to 2005, 259 pts underwent EUS examination for a suspected esophageal, gastric or duodenal submucosal lesion. In 121 pts EUS showed a hypoechoic intramural mass, that represents the basic feature of MTs. According to EUS criteria settled by us, these patients were divided into four groups, corresponding to a specific diagnostic hypothesis. Group 1 (leiomyoma): very low echogenicity (equal to that of the normal proper muscle) and homogeneous internal echo, regular margins, often bordered by a thin echorich line. Group 2 (GIST): low echogenicity, but higher than that of proper muscle and slightly heterogeneous internal echo, regular margins, sometimes with a hypoechoic halo. Group 3 (GIST suspicious of malignancy): echofeatures similar to group 2, but markedly heterogeneous internal echo. Group 4 (malignant MTs): echofeatures similar to group 3, but irregular margins and infiltration of adjacent layers. 38 pts were operated on. Surgical treatment, planned on the basis of EUS diagnosis, ranged from extramucosal enucleation of the tumor to wide resections. Compared with histology, EUS overall accuracy was 76%. Sensitivity and specificity were 87% and 91% for diagnosis of leiomyoma; 100% and 75% for diagnosis of GIST; 69% and 92% for diagnosis of malignant MT. Surgical procedure resulted to be adequate in all but three cases. Although the number of patients is small, criteria we adopted for EUS diagnosis seem to be helpful to plan surgical therapy.