Usefulness of morphological characteristics for the differentiation of benign from malignant solitary pulmonary lesions using HRCT

The aim of this study was to analyze different characteristics on high-reso lution computed tomography (HRCT) that help differentiate benign solitary p ulmonary lesions (BSPLs) from malignant solitary pulmonary lesions (MSPLs). High-resolution computed tomography was performed on 104 consecutive patie nts with SPLs. The whole lesion was examined with a slice thickness of 1 mm and a 12-cm field of view. All lesions were surgically excised within 24 h of the CT examination. Satellite nodules, cavitations, and necrosis were f ound only in MSPLs. Useful characteristics for the differentiation of BSPLs from MSPLs were the presence of spicules (p < 0.00005), spicules extending to the visceral pleura (p < 0.0005), the vessel sign (p < 0.0005), pleural retraction (p < 0.001), circumscribed pleural thickening (p < 0.001), the bronchus sign (p < 0.005), the presence of ground-glass attenuation adjacen t to the SPL (p < 0.01), the density of the lesion (p < 0.05), and the leng th of spicules (p < 0.05). Using the significant characteristics p < 0.01 f or the identification of MSPLs, a sensitivity of 91.4% and a specificity of 56.5% (accuracy of 83.7%) was found. A precise morphological assessment of the periphery of the pulmonary lesion is necessary. The HRCT technique is useful in differentiation of BSPLs from MSPLs. However, metastases strongly resembled benign lesions in terms of size and edge type, and chronic infla mmatory pseudotumors as a group mimic MSPLs.