[Clinical analysis of intrapulmonary lymph nodes]

We encountered 12 cases (9 men, 3 women) of intrapulmonary lymph nodes, discovered by chest radiography or chest CT and identified by thoracoscopic lung biopsy (in 10 cases), open lung biopsy (1 case) or lobectomy (1 case). We also studied the literature related to intrapulmonary lymph nodes in Japanese. Many intrapulmonary lymph nodes were found in the lower lung field, few in the upper lung field. All intrapulmonary lymph nodes were spherical and were located under the pleura, but we were not able in some cases to differentiate them from malignancies by the CT scanfindings. We could not diagnose them or rule out malignancy before surgery. Pathological findings revealed that all of them showed anthracosis. Silicotic changes were found in three cases. We consider that thoracoscopy is useful in making a definite diagnosis if peripheral pulmonary lesions cannot be diagnosed. We emphasize that intrapulmonary lymph nodes should be taken into consideration in differential diagnoses of small nodular lesions in the lung.