A Simple Computed Tomography Scoring System to Predict Histological Malignancy of Solitary Fibrous Tumors of the Pleura

Purpose: The aim of the present study was to define the very first score enabling discrimination between benign and malignant solitary fibrous tumors of the pleura (SFTPs), on the basis of reliable preoperative CT features.
Methods: Between December 2004 and November 2012, 56 patients underwent complete resection for SFTP at six institutes. CT scans were reviewed retrospectively, and a diagnostic scoring system for predicting malignant SFTP preoperatively was designed.
Results: Univariate analysis revealed seven significant predictors of malignant SFTP: tumor size ≥ 10 cm (p=0.002), tumor heterogeneity spontaneously (p=0.019) or after contrast medium injection (p=0.029), existence of intratumoral fluid density areas (p=0.011), a pleural effusion (p=0.01), measurable (diameter >1 mm) intratumoral vessels (p=0.019), a hypervascular character (visible intratumoral vessels and/or intense enhancement) (p=0.001). A scoring system based on these seven CT features, each assigned 1 point, and with a cut-off of 4 points, could predict malignant SFTP with a specificity of 85% and a sensitivity of 48%.
Conclusion: Our scoring system using seven CT features (tumor size ≥ 10 cm, tumor heterogeneity with or without contrast injection, intratumoral fluid density areas, pleural effusion, measurable intratumoral vessels, and a hypervascular character of the tumor) may be helpful for predicting histological malignancy of solitary fibrous tumors of the pleura.