Mesothelioma

Definition: malignant tumor that develops from mesothelial cells

Epidemiology

• Sex: ♂ > ♀ (3:1)

• Age range: ∼ 40–70 years

Etiology

• Secondary to asbestos exposure

• Alcohol, smoking, and diet do not increase the incidence of mesothelioma.

Pleural mesothelioma (most common)

Peritoneal mesothelioma (rarely)

Pericardial mesothelioma (very rarely)

Dyspnea and nonpleuritic chest pain (most common)

Fever, sweats, weight loss, fatigue

Features of pleural effusion: dull percussion; absent or reduced breath sounds on affected side

Pleurocentesis : bloody (exudative) pleural effusion

Imaging (chest x-ray and CT)

• Multiple nodular pleural lesions (pleural thickening)

• Ipsilateral hemothorax

• Reduced size of ipsilateral lung fields

• Obliteration of the diaphragm

Laparoscopy, thoracoscopy, and pleuroscopy with stained biopsy: reveal mesothelioma cells and psammoma bodies

• Risk of implantation metastasis. [8]

• It is important to differentiate mesothelioma from adenocarcinoma.

  • Immunohistochemistry: Mesothelioma often stains positive for mesothelin, serum mesothelin-related protein (SMRP), calretinin, cytokeratin 5/6 (negative in most adenocarcinomas), and vimentin. [9]

  • Electron microscopy shows tumor cells with long and slender microvilli (in contrast to the short and stubby microvilli found in adenocarcinomas), tonofilaments, and desmosomes.

Radiation, with or without chemotherapy (cisplatin and pemetrexed)

Surgery (pleurectomy or pneumonectomy) may be indicated in cases with severely impaired pulmonary function

Prognosis: poor, with a mean survival time of ∼ 1 year