Eosinophilic effusions: A clinicocytologic study of 12 cases.

EEs are uncommon. They mostly occur in young adult males. There are three cytomorphologic patterns that correlate with peripheral eosinophilia. Etiologies are diverse or obscure. EEs with a very high eosinophilia are less likely malignant, tuberculous, parasitic, and seldom associated with drugs. Cytopathologists should be aware of certain potential diagnostic pitfalls. Correct cytologic recognition is clinically important since some causes are treatable.