Nejm 2005;353:1591

Cause:Neoplasia from asbestosis; perhaps simian virus 40 is a cofactor

Pathophys:Quite malignant; ~20% are abdominal (peritoneal), which are all associated with heavy asbestos exposures, unlike often transient exposures of pulmonary types

2.5 cases/million population/yr. Most (all?) from asbestos exposure (Nejm 1969;280:488)

Sx:Nonpleuritic pain and/or dyspnea (95%). Pulmonary osteoarthropathy arthritis pain (distal extremities with periosteal new bone formation), often severe; benign types of mesothelioma have pulmonary osteoarthropathy 100% of the time, and it goes away with surgical rx

Si:Clubbing; ascites with peritoneal type

Rapid demise in <12 mo, usually about 4 mo after dx; die from primary lesions, not metastases usually. 0-10% 5-yr survival with rx

Pericardial effusions; small bowel obstructions with peritoneal types

Lab:

Chem:Osteopontin level >48 ngm/cc, 77% sens, 85% specif (Nejm 2005;353:1664); serum mesothelin-related protein elevated, 84% sens, 98% specif

Path:Pleural fluid cytology often hard to interpret because malignant mesothelial cells can appear normal; thorascopic bx usually diagnostic

Xray:Chest xray or CT shows pleural plaques (calcified); pulmonary fibrosis in 20% of pulmonary types, 50% of abdominal types; pleural effusions usually

Rx: Debatable (Ann IM 1977;87:618) if anything helps; perhaps chemoRx w pemetrexed (Alimta) w B₁₂ and folate (Med Let 2004;46:31)