CT diagnosis of pleural dissemination without pleural effusion in primary lung cancer

We retrospectively reviewed the CT scans of 25 primary lung cancers with disseminated pleural nodules or minimal malignant pleural effusions that were not recognized preoperatively. Special attention was devoted to abutting interlobar fissures, thick major fissures, and disseminated nodules on the chest wall, the diaphragm, and in the interlobar fissures. Among 10 primary tumors abutting interlobar fissures, nine (90%) had at least one of these findings. Among 15 primary lung tumors which did not abut interlobar fissures, four (27%) had at least one of these findings. We conclude that CT is a useful modality for detecting the pleural dissemination of primary lung cancers when primary lung cancers abut interlobar fissures even if no pleural effusion is detectable on CT.