Pleural fluid macrophages in lung infarct. Evidence and origin

In this study, which was undertaken after a personal error of diagnosis, we have tried to demonstrated why the cells found in the pleural fluid look alike cancerous cells and this aim has obviously lead us to discuss the origin of the abnormal cells. The cytologic and cytochemical study of pleural fluid cells in 9 cases of lung infarction and the comparizon with pathological patterns has lead the authors to believe that the abnormal cells present in the fluid are not mesothelial cells. The cytochemical stain on the smears and on the lung sections, evidencing iron pigment in the cytoplasma of some cells has lead us to consider them as alveolar macrophages. The simple technic may help in the diagnosis of lung infarction when the clinical features are not enough convincing.