Pleuritis by radiation: reports of two cases.

Two cases of pleuritis by radiation, diagnosed by cytology studies of the pleural fluid, are reported. The clinical picture was that of a respiratory infection, with nonproductive cough and pleuritic chest pain. Chest x-ray studies showed a small pleural effusion that was confirmed by a thorax puncture. The aspirated fluid was hemorrhagic, and Papanicolaou studies were negative for tumor cells. However, multiple reactive mesothelial cells with vacuole formation within the cytoplasm and nuclei were seen. The differential diagnosis of pleuritis by radiation should include infectious pleuritis as well as pleural metastasis. A history of previous radiation and the typical findings in cytologic studies are important to confirm the diagnosis.