Clinicopathological and Molecular Factors, Risk Factors, Treatment Outcomes and Risk of Recurrence in Mesenteric and Retroperitoneal Extragastrointestinal Stromal Tumors.

Abstract

The objective of the present study was to determine the clinicopathological factors and treatment outcomes of patients suffering from mesenteric or retroperitoneal extragastrointestinal stromal tumors (EGISTs). A detailed search in PubMed, using the key words "extragastrointestinal stromal tumors" and "EGIST", found eight studies fulfilling the criteria of this study. Thirty-six patients with a mesenteric and 24 patients with a retroperitoneal EGIST were analyzed, with a follow-up period ranging from 2 to 192 months. Retroperitoneal tumors presented as larger tumors than mesenteric ones, with 95% and 93% immunohistochemical positivity for CD117 antigen, respectively. Surgical resection was performed in 91% of cases, with 57% of patients with mesenteric and 70% of patients with retroperitoneal EGISTs being alive at the last follow-up. EGISTs most commonly are of considerable size and usually with a high mitotic count, rendering them high-risk tumors. Tumor necrosis, nuclear atypia, tumor histology, and mutations in the tyrosine kinase KIT or platelet-derived growth factor receptor A (PDGFRA) gene, seem to influence tumor behavior.