Abstract
Background : Sarcomatoid mesothelioma cells are scarcely detected in pleural effusions. We report a case in which a few large atypical cells were detected on fluid cytology.
Case : A 77-year-old man with a past history of asbestos exposure was detected by chest CT to show diffuse pleural thickening on the right side. The patient died approximately a month after being diagnosed to have malignant mesothelioma. Pleural fluid cytology showed a few solitary atypical large cells with increased N/C ratio, centrally placed nuclei, distinct nucleoli and dense cytoplasm in a background of lymphocytes and neutrophils. Immunocytochemical study was performed on a bleached specimen and no reactivity for calretinin was found. Histologically, pleural biopsy revealed spindle or oval tumor cells with vesicular nuclei, conspicuous nucleoli and eosinophilic cytoplasm proliferating in an abundant fibrous stroma. Mitotic figures were often observed. The tumor cells were immunoreactive for cytokeratin (CAM5.2), calretinin, D2-40, thrombomodulin and CD44s.
Conclusion : Sarcomatoid mesothelioma cells can scarcely be differentiated from pleural sarcomas, large cell carcinoma and pleomorphic carcinoma of the lung on the basis of cytology alone. Clinical information, including imaging study findings as well as the findings of pleural fluid cytology, pleural biopsy and their immunohistochemical findings should be concurrently considered in the diagnosis of sarcomatoid mesothelioma.
