Imaging features of gastric stromal tumors: radiologic-pathologic correlation. Report of 4 cases.

Goal. This study concerns the new anatomo-pathologic semantics of the ancie nt gastric leiomyoblastoma that become gastric stromal tumors (GST) and ide ntified as stemming of "pace-maker" cells of Cajal related to the immunohis tochemical characterization of the phenotype. Material and methods. We limited the study to the mesenchymatous tumors to "pacemaker' cells. For this purpose, we report four documented observations of gastric stromal tumors correlated to the histology and to the immunohis tochemical study. Results, Although some signs are often described (exogastric development, h eterogeneity with cystic and necrotic component, predominating peripheral e nhancement..), radiological aspects of these tumors are not specific becaus e, analogues to the other mesenchymal tumors (leiomyoma or schwannoma). The topographic diagnosis is difficult, realized by echoendoscopy, CT scan and MRI. The irregularity of contours evokes the malignancy as hemoperitoneum. GST do not show lymphophilic behavior that differentiates them from the ad enocarcinomas and gastric lymphomas. The surgical treatment is the best tre atment, allowing the immuno-histological diagnosis of certainty from the co mplete operative specimen. Conclusion. Some tumors are difficult in classifying despite classic histol ogy necessitating immuno-histochimical tests for the identification of musc ular, nervous, autonomous nervous system flexion of mesenchymatous tumors w ith epithelioid or spindle cells of the gastrointestinal tract. Then a radi o-clinical follow-up is therefore indicated: the evolution is the alone rea l marker of malignancy.