[Pleural eosinophilia: its diagnostic and prognostic significance].

Pleural eosinophilia (PE) has been usually associated with a good prognosis. Trying to clarify the diagnostic and prognostic significance of those effusions, we studied 50 consecutive PE from our Pleural Unit. Forty four of them met criteria of exudate and six of transudate. PE was significantly more frequent in traumatic pleural effusions, and less frequent in malignant and parapneumonic effusions. There were not statistical differences in the number of malignant effusions associated or not with eosinophilia. We conclude that the presence of pleural eosinophilia is an useful parameter to exclude tuberculous pleural effusions, but not to lessen the likelihood of malignancy. Pleural eosinophilia in an idiopathic pleural effusion means a good prognosis.