Association between CT imaging features and KIT mutations in small intestinal gastrointestinal stromal tumors

Small intestinal gastrointestinal stromal tumors (GISTs) have different clinical outcomes when KIT mutations are in exons 11 or 9, which are also the most common sites of neoplastic KIT mutations. The purpose of this study is to evaluate the CT imaging features in those two groups. A total of 35 patients were enrolled, and both quantitative and qualitative CT imaging features were compared between patient groups with KIT exon 9 mutations (KIT-9) and exon 11 mutations (KIT-11). The KIT-9 group was statistically associated with a tumor size larger than 10cm and a higher enhancement ratio when compared with those of the KIT-11 group (both P < 0.05). For the enhancement ratio, the receiver operating characteristic curve indicated a cut-off value of 1.60 to differentiate KIT-9 from KIT-11 tumors. Additionally, tumor necrosis was more commonly seen in the KIT-9 group. In multivariate analysis, tumor size (beta = 0.206; P= 0.022) and KIT-9 (beta = 0.389; P= 0.006) were independent factors associated with tumor necrosis. Taken together, KIT-9 mutant tumors tended to have CT imaging features indicative of more aggressive neoplasms. These findings may be helpful in identifying more aggressive small intestinal GISTs and optimizing treatment.