OBJECTIVE: To identify computed tomography (CT) predictors of malignancy, from a retrospective study of preoperative CT scans of patients with solitary fibrous tumors (SFT) of the pleura.
PATIENTS AND METHODS: The CT scans of 56 patients with histopathologically confirmed SFT (33 women and 23 men; mean age, 60years) who underwent surgery between December 2004 and November 2012 were retrospectively analyzed by three radiologists working in consensus, blinded to the final histological diagnosis.
RESULTS: SFT was asymptomatic and incidentally discovered in 22 patients (45.8%). Resection specimen analysis (R0 resection in all cases) revealed that 23 tumors (41%) were malignant. The CT features, which significantly differed between malignant and benign SFTs were tumor size (P=0.002) with a discriminative threshold value of 10cm, tumor heterogeneity before (P=0.02) and after (P=0.03) intravenous administration of iodinated contrast material, presence of intratumoral hydric attenuation areas (P=0.01), pleural effusion (P=0.01), measurable intratumoral vessels (P=0.02), hypervascularization with visible intratumoral vessels and/or marked enhancement (P=0.001). Presence of intratumoral calcifications (P=0.2) and maximum post-contrast enhancement value (P=0.6) were not significantly different between the two groups.
CONCLUSION: A size greater than or equal to 10cm, hypervascularization, attenuation heterogeneity and association with pleural effusion are individual variables that suggest malignant SFT on CT.