Mesothelioma

Question 1

What is mesothelioma?

Answer 1

Malignant mesothelioma is an aggressive epithelial neoplasm arising from the lining of the lung, abdomen, pericardium or tunica vaginalis.

Question 2

What is the chief causative agent of mesothelioma?

Answer 2

Asbestos.
Mesothelioma is one of the few cancers related directly to environmental exposure.
Other causes include:
Prior exposure to radiotherapy
Genetic predisposition e.g. mutation of the BAP1 gene

Question 3

How do patients present with mesothelioma?

Answer 3

Dyspnoea and chest pain.

It is often associated with unilateral pleural effusion and pleural thickening.

Question 4

Classification of mesothelioma

Answer 4

Anatomical variants: 
Pleural (90%) 
Peritoneal (5-10%) 
Pericardial (<1%) 
Testicular (<1%)
Histological subtypes: 
Epithelial 
Biphasic 
Sarcomatoid

Question 5

Signs and symptoms of mesothelioma

Answer 5

Dyspnoea 
Diminished breath sounds 
Dullness to percussion 
Chest pain 
Cough 
Abdominal distension and/or pain 
Constitutional symptoms- fatigue, fever, sweats and weight loss.

Question 6

Risk factors of mesothelioma?

Answer 6

FHx 
Hx of asbestos exposure 
Simian virus 40 (SV-40) 
Age between 60-85 years 
Male sex 
Radiation exposure

Question 7

Investigations for mesothelioma

Answer 7

CXR 
CT scan of the chest and upper abdomen with IV contrast 
Thoracentesis 
Pleural biopsy 
Chest MRI 
PET scan

Question 8

Differentials of mesothelioma

Answer 8

Benign reactive mesothelial hyperplasia
Benign asbestos-related pleural reactions
NSCLC
SCLC 
Metastatic cancer

Question 9

Staging of mesothelioma

Answer 9

T stage:
TX: Primary tumour cannot be assessed
T0: No evidence of primary tumour
T1: Tumour limited to the ipsilateral parietal pleura, with or without involvement of:
Visceral pleura
Mediastinal pleura
Diaphragmatic pleura
T2: Tumour involving each of the ipsilateral pleural surfaces (parietal, mediastinal, diaphragmatic, and visceral pleura), with at least one of the following:
Involvement of the diaphragmatic muscle
Extension of tumour from visceral pleura into the underlying pulmonary parenchyma
T3: Locally advanced but potentially resectable tumour. Tumour involving all of the ipsilateral pleural surfaces (parietal, mediastinal, diaphragmatic, and visceral pleura), with at least one of the following:
Involvement of the endothoracic fascia
Extension into the mediastinal fat
Solitary, completely resectable focus of tumour extending into the soft tissues of the chest wall
Non-transmural involvement of the pericardium
T4: Locally advanced, technically unresectable tumour. Tumour involving all of the ipsilateral pleural surfaces (parietal, mediastinal, diaphragmatic, and visceral pleura), with at least one of the following:
Diffuse extension or multifocal masses of tumour in the chest wall, with or without associated rib destruction
Direct trans-diaphragmatic extension of the tumour to the peritoneum
Direct extension of tumour to the contralateral pleura
Direct extension of tumour to mediastinal organs
Direct extension of tumour into the spine
Tumour extending through to the internal surface of the pericardium with or without a pericardial effusion; or tumour involving the myocardium.
N stage:

NX: Regional lymph nodes cannot be assessed
N0: No regional lymph node metastases
N1: Metastasis to the ipsilateral bronchopulmonary, hilar, or mediastinal (including the internal mammary, peri-diaphragmatic, pericardial fat pad, or intercostal) lymph nodes
N2: Metastases in the contralateral mediastinal, ipsilateral, or contralateral supraclavicular lymph nodes.
M stage:

M0: No distant metastasis
M1: Distant metastasis.

Question 10

Complications of mesothelioma

Answer 10

Surgical morbidity
Acute radiation morbidity
Radiation pneumonitis
Chemotherapy-induced haematological toxicity
Postoperative mortality
Distant metastases
Local invasion of crucial thoracic structures.