History and exam

Key diagnostic factors

common

family history

Family history of mesothelioma and other cancers, including uveal melanoma, renal cell carcinoma, and cutaneous melanoma, may suggest an underlying germline BAP1 mutation.[19][20]

Germline mutations in the gene encoding BRCA1 associated protein-1 (BAP1) can predispose carriers to mesothelioma.[24]

history of asbestos exposure

About 80% of patients have a history of asbestos exposure.[12] Occupational history regarding the type of work performed (e.g., naval shipboard service; ship building; construction and maintenance; vehicle brake mechanic; production of asbestos products such as cement, insulation, tiles, shingles, gaskets, brakes, or textiles) may provide some clues.

age between 60 and 85 years

The latency period between exposure to asbestos and development of malignant pleural mesothelioma is 20 to 40 years. Therefore, most patients are older adults.[3][4][28]

shortness of breath

Increasing shortness of breath, typically due to a large pleural effusion or trapped lung, is the most common symptom. Moderate or severe dyspnoea occurs in about 40% of patients.[41]

diminished breath sounds

Usually a result of pleural effusion, trapped lung, or bronchial obstruction.

dullness to percussion

Suggests presence of a pleural effusion on the affected side.

Other diagnostic factors

common

male sex

Male to female ratio in the US is 3:1, probably reflecting occupational exposure to asbestos.[3]​​[7]​​​​

chest pain

Although mesothelioma does not commonly invade the chest wall, chest pain is a common symptom, occurring in about 25% of patients.[41]

cough

Usually dry and non-productive.

constitutional symptoms

Include non-specific findings such as fatigue, fever, sweats, and weight loss.

Moderate or severe fatigue occurs in about 30% of patients.[41]

uncommon

abdominal distension and/or pain

Uncommon, but can occur as a consequence of extension to the abdominal cavity with resultant ascites; often a late presentation of disease. It is more often seen as a presenting symptom of peritoneal mesothelioma.

Risk factors

strong

asbestos exposure

Considered the principal risk factor for developing malignant pleural mesothelioma. This association was first reported in 1960 among patients working in the vicinity of South African asbestos mines and has since been confirmed by innumerable epidemiological studies.[25][26]

In clinical studies, about 80% of patients with malignant pleural mesothelioma have a history of asbestos exposure.[12] Occupational history regarding the type of work performed (e.g., naval shipboard service; ship building; construction and maintenance; vehicle brake mechanic; production of asbestos products such as cement, insulation, tiles, shingles, gaskets, brakes, or textiles) may provide some clues.

There are three main types of asbestos: chrysotile (white asbestos), amosite (brown asbestos), and crocidolite (blue asbestos). Crocidolite, which is composed of long and narrow fibres, seems to be the primary type of asbestos associated with the development of mesothelioma.[27] The mechanism of carcinogenesis is not known with certainty.

age 60 to 85 years

The latency period between exposure to asbestos and development of malignant pleural mesothelioma is 20 to 40 years, and therefore most patients are older adults.[3][4][28]

weak

asbestos exposure during home maintenance and renovation

There is an increasing incidence of mesothelioma in people who have been exposed to asbestos during home maintenance and renovation.[29]

male sex

Males are significantly more affected than females, likely reflecting occupational exposure to asbestos.[3][7]

radiation exposure

Radiation is a known carcinogen and has been shown to increase the risk of many types of cancer. Case reports and epidemiological studies have suggested that radiation exposure is associated with the development of mesothelioma.[16] This includes patients treated with radiotherapy for other malignancies or benign conditions, as well as patients treated with the contrast medium thorotrast, which contains radioactive thorium dioxide. Patients with radiation-associated mesothelioma tend to be younger than patients with asbestos-associated mesothelioma.[30]

genetic predisposition

Germline mutations in the gene encoding BRCA1 associated protein-1 (BAP1) can predispose carriers to mesothelioma.[24] Other cancers, in particular uveal and cutaneous melanomas, basal cell carcinomas, and renal cell carcinomas, have been described in these individuals.[19][20]

simian virus 40 (SV-40)

The oncogenic DNA simian virus 40 (SV-40) has been detected in human mesotheliomas and can induce mesothelioma-like tumours in rodents. What role, if any, SV-40 plays in the pathogenesis of malignant pleural mesothelioma is unclear.[18]

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