|Case of the Week - Patient Summary 4792|
Peer Reviewed and Certified -
|Demographics: 62 y.o. man|
|History & Chief complaint:|
| 62 y/o man with a history of malignant effusion |
|Physical exam: Not Available|
|Summary of Findings:|
|1. PA/LAT chest radiographs demonstrates left pleural effusion.
2. A contrast-enhanced CT of the chest demonstrates left pleural effusion with enhancing and irregularly thickened pleura. There is focal nodularity and enhancing nodularity of the mediastinal pleura. No significant adenopathy and no evidence of chest wall abnormality.
3. New findings on an MRI of the chest include a small right pleural effusion indicating possible malignant involvement of the right pleura. No chest wall lesions or new diaphragmatic lesions were detected.
| Malignant Mesothelioma (Cells were obtained from thoracocentesis and identified by immunohistochemical staining.) |
|Patient Specific Discussion: (Also Read the Disease Discussion)|
|Histological identification requires special staining procedures and careful analysis. Because the tumor may be composed of mesenchymal cells, epithelial cells, or both, distinguishing it from benign reactive mesothelial cells, adenocarcinoma or sarcoma can be difficult. Asbestos fibers are not found in the tumor|
|Although a chest radiograph may detect a diffuse pleural abnormality, the most critical information about the nature of a pleural disease process is best evaluated by CT. Both benign and malignant pleural processes have been found to have some characteristic CT features, although many of these are shared. Benign pleural disease, for instance, is most often smooth and uninterrupted, extending over about one quarter of the chest wall or more. Presentation frequently includes pleural effusion and calcification generally signals benignity. This definition is not without controversy. Malignant disease is more often nodular and irregular. It best distinguishes itself when there is involvement of the mediastinal pleural or focal fissural thickening. Enhancement on CT imaging is usually easily seen. Calcification is uncommon, but can be seen in up to 20% of cases of mesothelioma.
Diffuse mesothelioma is an uncommon but dire diagnosis . Two to three thousand cases are seen in the US each year. Mean survival is 11 months. Up to 80% of cases are associated with exposure to asbestos (most often crocidolite) after an average latency period of 35 years. The much less common focal form, sometimes known as a pleural fibroma, is not associated with asbestos exposure. Patients with diffuse mesothelioma frequently present with cough, weight loss, dyspnea and chest pain. The most common radiographic finding is pleural effusion Further study is best performed with CT. The most consistent CT radiographic finding is pleural thickening (92%). Additional findings include thickening of the interlobar fissures (86%) and pleural effusion (74%). Nodular, enhancing pleura – particularly at the interlobar fissures and mediastinum – is highly suggestive of malignant pleural disease. . The tumor arises from the parietal pleural.
Until thoracocentesis or pleural biopsy is performed, mesothelioma or metastatic disease cannot be distinguished. CT commonly demonstrates lymph node involvement (50%) but may underestimate the degree of chest wall and diaphragmatic involvement. Computed tomography’s utility lies in assessing the extent of disease and aiding in determining resectability. For diagnostic accuracy in staging it is nearly equivalent to MRI, but it is considered the standard imaging choice due to its lower cost. MRI is superior to CT in demonstrating diaphragmatic or chest wall involvement not seen on CT.