Diagnostic usefulness of endobronchial ultrasound-guided transbronchial needle aspiration in a case with malignant pleural mesothelioma.

A 74-year old man was admitted to our hospital with right diffuse pleural thickening and effusion and with subcarinal lymph node swelling. The effusion obtained by thoracentesis showed no malignant cells, although positron emission tomography showed abnormal uptake in the right pleural thickening and subcarinal lymph node. Histopathological examination of the lymph node specimens obtained by endobronchial ultrasound-guided transbronchial needle aspiration showed a sheet of epithelioid-like large atypical cells. The tumor cells were immunohistochemically positive for calretinin and cytokeratin 5/6, and negative for CEA and TTF-1. Therefore, malignant pleural mesothelioma of epithelioid type was diagnosed.