[Evaluation of rounded atelectasis induced by exposure to asbestos]

We encountered 19 patients of rounded atelectasis induced by exposure to asbestos from 2000 to 2007. All patients were men whose ages arranged from 60 to 89 years with a mean of 74.2 years. Twenty rounded atelectasis were present in the right lung and 5 in the left lung. Five patients had 2 rounded atelectasis. In 21 rounded atelectasis were found in Segment 10 and while other 2 found in S1 and each in S5 and 9. Eleven patients were diagnosed with no symptoms through medical examinations. Other 8 patients complained of dyspnea, chest pain and cough. Thirteen patients complicated with benign asbestos pleurisy and only 3 patients accompanied asbestosis. Eighteen patients (95%) displayed pleural plaques and 15 patients with calcified plaques. Ten patients had been exposed to asbestos in the shipyards and 4 in construction works and other 5 patients had also exposed by occupational exposure to asbestos. The mean period of exposure to asbestos was 26.6 years and the mean latency periods from the first asbestos exposure to the diagnosis of rounded atelectasis were 51.6 years. An autopsied patient had 18,100 asbestos bodies per 1 g of dry lung tissue which meant the heavy asbestos exposure. High incidence of pleural plaques and long period of latency from the first exposure to the appearance of rounded atelectasis in this study suggested that rounded atelectasis might appear less high-dose exposure to asbestos than former patients who were reported 6 years ago.