Role of CT in Differentiating Malignant Focal Splenic Lesions

Objective: The purpose of this study was to asses the CT findings and clinical features differentiating malignant from benign focal splenic lesions. Materials and Methods: Among 673 patients with splenectomy, we included 114 patients with pathologically confirmed focal splenic lesions (malignant = 66, benign = 48). Two radiologists retrospectively assessed CT findings including: size, number, solid component, margin, wall, calcification, contrast-enhancement, lymph node (LN) enlargement and possible malignancy. We assessed clinical features including age, sex, underlying malignancy, fever, and leukocytosis. Multivariate logistic regression analysis was performed to identify significant predictors of malignant lesion. We used receiver operating curve analysis for determination of diagnostic performance. Results: Common findings of malignant lesions include enhanced, mainly solid, ill-defined margin, absence of splenomegaly, absence of the wall, absence of calcification, LN enlargement, and presence of underlying malignancy (p < 0.05). Among them, mainly solid features (odds ratio [OR], 39.098, p = 0.007), LN enlargement (OR, 6.326, p = 0.005), and presence of underlying malignancy (OR, 8.615, p = 0.001) were significant predictors of malignancy. The mean size of benign splenic lesions ($5.8{\pm}3.3cm$) was larger than that of malignant splenic lesions ($4.0{\pm}3.4cm$). Diagnostic performance of CT findings by two reviewers using receiver operating characteristic curve analysis for differentiation of malignant lesions was 0.856 and 0.893, respectively. Conclusion: Solid nature of the splenic mass on CT images, LN enlargement, and presence of underlying malignancy are significant predictors of malignant splenic lesion.