|Print Date:||May 21, 2013, 6:10 am|
|Title||Biphasic Mesothelioma involving the R lung, pleura, and hilar nodes|
|Text||Diffuse malignant mesothelioma is an uncommon and fatal neoplasm of the serosal lining of the pleural cavity, peritoneum, or both. The development of malignant mesothelioma has a strong correlation with asbestos exposure. Of the various types of asbestos fibers, crocidolite, amosite, and tremolite are highly carcinogenic. However, the amount of asbestos exposure needed to produce malignant pleural mesothelioma, or the dose-response relationship, is unknown. Five to ten percent of those exposed develop the disease after a 20 to 40 year latency. Histologically, there are epithelial, sarcomatous, and mixed (biphasic) subtypes. Common radiographic findings include a moderate to large amount of pleural effusion with or without a pleural mass, or diffuse pleural thickening with or without an effusion. Pleural effusion occurs in 30 to 80% of patients with malignant mesothelioma. Although a mediastinal shift to the contralateral side is usually seen in association with massive pleural effusions, it is not a common finding in patients with mesothelioma. Instead, there may be evidence of volume loss on the affected side, with narrowing of the intercostal spaces, elevation of the hemidiaphragm, and ipsilateral shift of the mediastinum. Diffuse, unilateral pleural thickening occurs in up to 60% of patients. Sheet-like or lobulated pleural thickening may encase the lung, grow into the fissures, and create a pleural rind. Mesothelioma may also present as discrete pleural masses. Discrete pulmonary and hilar masses can also occur. Invasion of the chest wall occurs in advanced disease. CT is helpful both in the detection of other underlying signs of asbestos exposure, such as pleural plaques, and in determining the extent of tumor. Mesotheliomas are staged by the Butchart system as follows:I. Involvement of the ipsilateral parietal pleura, diaphragm, or pericardium II. Invasion into the chest wall or mediastinum, mediastinal lymph nodes III. Penetration of the diaphragm, contralateral pleural disease, or extrathoracic lymph nodes IV. Hematogenous metastases
Surgery, chemotherapy, and radiation therapy are viable treatment options. However, extrapleural pneumonectomies (removal of lung, parietal pleura, pericardium, and diaphragm) are reserved for stage I and II disease. The prognosis is uniformly poor, and distant hematogenous metastases may occur.
|References:||1. Freundlich IM, Bragg DB. A radiologic approach to diseases of the chest. Philadelphia: Williams and Wilkins, 1992.
2. Frasier RG, Pare JAP, Pare PD, Frasier RS, Genereux GP. Diagnosis of diseases of the chest. 3rd ed. Philadelphia: WB Saunders, 1991.
3. McLoud TC. Conventional radiography in the diagnosis of asbestos-related disease. Radiol Clin North Am 1992; 30:1177-1189.
4. Miller BH, Rosado-de-Christenson ML, Mason AC, Fleming MV, White CC, Krasna MJ. Malignant pleural mesothelioma: radiologic-pathologic correlation. RadioGraphics 1996; 16:613-644.
5. Wechsler RJ, Steiner RM, Conant EF. Occupationally induced neoplasms of the lung and pleura. Radio Clin North Am 1992; 30:1245-1268.
|Contributor||MS-4 USU Teaching File (Uniformed Services University)|
|Author||2Lt Victor Chang|
|Peer Reviewer||David S. Feigin, M.D. (Johns Hopkins Hospitals)|
|Record Number||: 4645|
|Category:||Neoplasm, malignant (NOS)|
|Location:||Chest, Pulmonary (ex. Heart)|
|Sublocation:||Pleura and cavity|
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