Rules for Classification

The classification applies only to malignant mesothelioma of the pleura. There should be histological confirmation of the disease.

Regional Lymph Nodes

The regional lymph nodes are the intrathoracic, internal mammary, scalene and supraclavicular nodes.

TNM Clinical Classification

T – Primary Tumour

TX	Primary tumour cannot be assessed
T0	No evidence of primary tumour
T1	Tumour involves ipsilateral parietal pleura only, with or without involvement of visceral, mediastinal or diaphragmatic pleura (Figs. 288, 289, 290a)
T2	Tumour involves the ipsilateral pleura (parietal or visceral pleura), with at least one of the following: Invasion of diaphragmatic muscle (Fig. 290b) Invasion of lung parenchyma (Fig. 290b)
T3	Tumour involves ipsilateral pleura (parietal or visceral pleura), with at least one of the following: Invasion of endothoracic fascia (Fig. 291a) Solitary focus of tumour invading soft tissues of the chest wall (Fig. 291b) Invasion into mediastinal fat (Fig. 292a) Non‐transmural involvement of the pericardium (Fig. 292b)
T4	Tumour involves ipsilateral pleura (parietal or visceral pleura), with at least one of the following: Chest wall, with or without associated rib destruction (diffuse or multifocal) (Fig. 293) Peritoneum (via direct transdiaphragmatic extension) (Figs. 294, 295a) Contralateral pleura (Fig. 296) Mediastinal organs (oesophagus, trachea, heart, great vessels) (Figs. 295b, 296) Vertebra, neuroforamen, spinal cord (Fig. 296) Internal surface of the pericardium (transmural invasion with or without a pericardial effusion) or involvement of the myometrium (Fig. 295b, 296)