Intrapulmonary lymph nodes detected by exploratory video-assisted thoracoscopic surgery: appearance of helical computed tomography.

The objective of this study was to analyze helical computed tomography (CT) findings of intrapulmonary lymph nodes (IPLNs), and to evaluate the diagnostic procedures to prevent unnecessary exploratory surgery. Between April 1997 and March 2000, we performed exploratory video-assisted thoracoscopic surgery (E-VATS) in 42 patients and in 8 patients (4 men, 4 women; 48 to 75 years of age, mean 57 years) IPLN was pathologically proven. Retrospectively, the appearances of IPLN in helical CT images were studied in detail. The diameter of the IPLNs varied from 4 to 10mm. Six nodules were located in the lower lobes and 2 nodule was in the lingula. Chest CT showed several malignancy-suggesting associated findings with pleural indentation (2/8), spicular radiation (2/8), fuzzy margins (4/8), and vascular involvement (2/8). Black colored anthracoses in 5 subpleural IPLNs were confirmed by thoracoscopy. One patient with two coin lesions was suggestive of lung metastasis of adenoidcystic carcinoma of the tongue, but one lesion was proven as IPLN, and the other as metastatic carcinoma. In conclusion, it is not possible to distinguish an intrapulmonary lymph node from a malignant lesion using the CT findings preoperatively. Therefore, a pathological study with E-VATS is necessary and sure procedure to exclude malignant disease under the present conditions.