Malignant Mesothelioma

 

• Background

  Pathology

  • Cancer arising from the mesothelium, the epithelial layer of the serosa.
  • 90% are in the pleural serosa. This typically leads to chest wall invasion, thoracic lymph node infiltration, and eventually metastases to the liver, lung, kidney, and bone.
  • 10% occur in the pericardial or peritoneal serosa.
  • Histological subtypes: sarcomatous, epithelial, or mixed.

  Relation to asbestos

  • Asbestos exposure – sometimes at very low levels – accounts for most cases.
  • There is around a 30-50 year latency between exposure and disease, so exposures later in life are not as problematic.
  • History of asbestos exposure can be identified in 90%, but only 20% have existing asbestosis.

• Signs and symptoms

  • Respiratory: SOB, dull chest pain, and signs of pleural effusion.
  • Systemic: weight loss, fever, fatigue.
  • Others: clubbing (especially if asbestosis also present), pericardial effusion.

• Investigations

  • CXR and chest CT: pleural effusion, pleural thickening, interstitial changes of asbestosis.
  • Aspiration of pleural effusion.
  • Biopsy. Can be CT or US-guided, or from video-assisted thoracoscopy for the best samples. Immunohistochemistry showing cytokeratin 5/6 helps distinguish mesothelioma from lung or metastatic adenocarcinoma (characterised by CEA).

• Management

  • Mainly symptomatic management.
  • Death is usually within 1 year, with chemotherapy perhaps adding around 3 months.
  • Prophylactic radiotherapy can be used to reduce seeding by the biopsy needle.
  • They may be entitled to compensation, so making the diagnosis is extremely important.