Pulmonary adenocarcinoma simulating malignant mesothelioma.

Adenocarcinoma of the lung with pleural involvement frequently resembles pleural epithelioid mesothelioma clinically as well as macro- and microscopically. Special stains, immunohistochemical studies, and electron microscopic studies are needed to differentiate these 2 tumors. We report a case of pleural involvement by adenocarcinoma, mimicking in the hematoxylin-eosin stain an epithelioid mesothelioma, correctly identified only after immunohistochemical and electron microscopic examinations.