[Reactive eosinophilic pleuritis]

Reactive changes in human pleura were studied 6 hrs, 1, 3 and 7 days after artificial pneumothorax. Thoracoscopically, grey-white deposits were seen which consisted of disorderly accumulation of monocytes, neutrophils, eosinophils and fibrin during the first hours. Later (the 3rd and the 7th days), the layer was observed formed of histiocyte-like cells and few multinuclear cells. The membrane on the pleura surface most likely represents a culture of monocyte cells. Morphologically, reactive eosinophilic pleuritis by the 7th day has a similarity with histiocytosis X; this may be the source of error diagnosis at the biopsy examination. Wrong interpretation of changes as a proliferative process, neoplasia or pleura tuberculosis is also possible.