Discriminative features of thin-slice computed tomography for peripheral intrapulmonary lymph nodes

Background: The use of computed tomography (CT) scans has increased the opportunities to detect small nodular shadows in peripheral lung fields. Intrapulmonary lymph nodes (IPLNs) are sometimes identified among these nodular shadows, and a differential diagnosis is often difficult. However, few descriptions of the CT findings of IPLNs, with regard to their potential for the differential diagnosis of lung cancer, have been published. Methods: From 2006 through 2011, 606 patients underwent thoracic surgery for pulmonary nodules. Nine patients (1.5%) had pathologically diagnosed IPLNs. We retrospectively reviewed the clinicopathological features and thin-section CT findings of the patients with IPLNs. We also compared these IPLN patients with 17 patients having small-sized lung cancer. Results: In six cases, the nodules were round, and linear density extending from the IPLNs was visualized in seven nodules. The nodules in IPLNs were located in the lower lobe, and the nodule borders were clearer than those of lung cancers. Six out of nine nodules were round, and linear densities were more easily visualized for the IPLNs. Conclusion: Medical specialists need to be familiar with the discriminative features of thin-slice CT for IPLNs not only to avoid performing unnecessary operations, but also to prevent the mis-staging of lung cancer