Effusion cytology in the diagnosis of malignant epithelioid and biphasic pleural mesothelioma

We reviewed the cytologic findings in pleural effusions of 36 patients in whom a diffuse epithelioid or biphasic malignant mesothelioma of the pleura developed between 1978 and 1988. Malignant neoplasms were diagnosed in 26 (72%) of the 36 patients. A specific diagnosis of a mesothelioma was rendered or suspected in 64% (23/36 patients). Mesothelioma was favored over adenocarcinoma in 81% (29/36) of patients with positive fluid cytologic findings. The contribution of effusion cytology to the final diagnosis and patient treatment was assessed. These data suggested that a cytologic diagnosis contributed useful information in most patients with malignant epithelioid and biphasic pleural mesotheliomas.