Pulmonary Nodules Resected for Suspected Metastsis from Extrapulmonary Malignancy: CT-Pathologic Correlation

Abstract

Purpose : To assess the relative frequency of benign and metastatic nodules in patients in whom nodules were resected due to suspected metastasis, and to compare the CT features of these nodules with pathologic findings in resected specimens. Materials and Methods : Ninety-four pulmonary nodules resected by pulmonary metastasectomy in 31 patients with extrathoracic malignancies were included in our study. We retrospectively analyzed the CT features of each nodule with regard to size, shape, margin characteristics, the presence or absence of cavity, location and distance from the pleura. Results : Among 94 resected nodules, 67 (71%) were metastatic, and 27 (29%), were benign. Among the pathologically benign nodules, involvement was as follows : fibrosis (n=14), intrapulmonary lymph node (n=7), necrosis (n=3), organizing pneumonia (n=2) and xanthogranulomatous inflammation (n=1). The mean diameter of metastatic nodules was 10.9 (range, 1-30) mm, and that of benign nodules 6.0 (range, 1-30) mm. Statistically significant differences in nodule size were found between the two groups (p 0.05), though CT revealed no significant differences in terms of shape, margin, the presence or absence of cavity, location and distance from the pleura. Conclusions : Twenty-nine percent of surgically resected nodules in patients with extrathoracic malignancies were benign. Although the possibility of metastatic nodule increases with larger nodule size, the correct diagnosis of pulmonary nodules requires histopathologic confirmation or monitoring of serial changes in nodule size.