[CT features and anatomic distribution of pleural dissemination in lung cancer].

Background: To study the CT appearance of lung cancer combined with pleural dissemination and its anatomic characteristics.

Methods: CT findings of 32 cases of lung cancer with pleural dissemination proved by surgery and pathology were analyzed.

Results: The main CT manifestations were pleural effusion (24 cases), visceral pleural dissemination with nodules (10 cases), parietal pleural dissemination with nodules (16 cases), and pleural thickening (31 cases). Out of the cases with visceral pleural disseminations, nodules distributed on the lung surface in 9 sites, while on the interlobular pleura in 10 sites. Parietal pleural dissemination with nodules were found in 45 sites which located on the diaphragmatic pleura, the costal pleura, the mediastinal pleura, and the pulmonary ligament. The diameters of the small nodules ranged from 2 to 5 mm, and the large nodules from 5 to 10 mm. There were direct invasion with tumor induced pleural thickening in 10 cases, while indirect invasion in 21 cases. In the later cases, 9 cases had parietal pleural thickening less than 10 mm, 4 circumferential pleural thickening, 5 mediastinal pleural involvement thickening, and 3 pulmonary ligament thickening.

Conclusions: Pleural effusion is the main manifestation of lung cancer combined with pleural dissemination. The CT features of lung cancer with pleural dissemination are the parietal and visceral pleural nodules, as well as the pleural thickening. The nodules are likely to distribute on parietal pleura of the diaphragmatic and the costal pleura, and they may transfer to the pulmonary ligament.The early small disseminating nodules are miliary in size, and only can be detected on the pulmonary window of chest CT scan.