Which of the following statements about the diagnosis and staging of mesothelioma is/are correct?

B. Open biopsy or thoracoscopy should be performed to obtain tissue for diagnosis.

C. Immunohistochemistry should be performed in all cases of suspected mesothelioma.

D. Chest CT and/or magnetic resonance imaging (MRI) are useful in the staging of mesothelioma.

DISCUSSION: Approximately 90% of patients with mesothelioma develop pleural effusion, but cytologic specimens from pleural fluid are inaccurate for the diagnosis of mesothelioma, and open or thoracoscopic biopsy is required. Accurate diagnosis of mesothelioma is difficult: the epithelial variant must be differentiated from adenocarcinoma, whereas the sarcomatous form often resembles benign sarcomas. Immunohistochemistry using a panel of antibodies, and sometimes electron microscopy, is required for all cases. Relentless local spread is typical, and chest CT or MRI is essential to evaluate potential local extension into the chest wall, pericardium, mediastinum, or diaphragm. Metastatic disease is less common and occurs late (if at all) in the disease course, so head CT and bone scans are indicated only if clinical findings are suspicious for metastasis.