Malignant Pleural Mesothelioma Diagnosed by Endobronchial Ultrasound-Guided Transbronchial Needle Aspiration
A 61-year-old woman presented with pleural effusion and recurrent pneumothorax. She underwent repeated thoracentesis, transbronchial lung biopsy (TBLB), bronchoalveolar lavage (BAL), and thoracoscopic pleural biopsy with talc pleurodesis. However, all examinations were non-diagnostic. VATS biopsy was considered but was not performed because of pleural adhesion.\nShe was admitted to our hospital because her respiratory symptoms did not improve. Chest radiography (CXR) and chest computed tomography (CT) revealed multifocal air-fluid levels, consolidation, and pleural thickness (). Positron emission tomography (PET) showed hyper-metabolic lesions in right upper paratracheal, right lower paratracheal, subcarinal, and right interlobar lymph nodes ().\nEBUS-TBNA was performed to obtain a tissue specimen for diagnosis of disease. Adequate tissue was obtained by 3 aspirations from the right upper paratracheal lymph node (#2R), 2 aspirations from the subcarinal lymph node (#7), and 3 aspirations from the right interlobar lymph node (#11R) ().\nPathologically, the tumor cells obtained from EBUS-TBNA procedure showed dominant papillary architecture (). Nevertheless, at cytology smear, tumor cells were relatively dyscohesive and demonstrated narrow windows (figure not shown). Pathologic differential diagnoses were malignant mesothelioma and pulmonary adenocarcinoma. By immunohistochemical stainings, tumor cells were strongly labeled for anti-calretinin antibody both in cytoplasm and nucleus (). Positive reactions for anti-cytokeratin 5/6 () and anti-Wilms tumor 1 () antibodies were also noted. Nevertheless, immunohistochemical staining for anti-thyroid transcription factor-1 antibody was negative (), consistent with malignant mesothelioma rather than pulmonary adenocarcinoma.\nPET findings showed multiple lymphadenopathies in both supraclavicular areas (N3 lymph node). Her clinical stage was IV. Two weeks after the diagnosis, she received premetrexed/cisplatin chemotherapy.