Malignant pleural mesothelioma (staging)

A number of staging systems have been described for staging of malignant pleural mesothelioma. Below is the International Mesothelioma Interest Group TNM staging system.


T - Tumor
  • Tx: primary tumor cannot be assessed
  • T0: no evidence of primary tumor
  • T1a
    • potentially resectable
    • only parietal pleura
    • no mediastinal pleural involvement
  • T1b
    • potentially resectable
    • parietal pleura AND
    • scattered foci of mediastinal pleural involvement
  • T2
    • potentially resectable
    • parietal and visceral pleural involvement, and / or
    • pulmonary parenchymal involvement and/or
    • diaphragmatic muscle involvement
  • T3
    • potentially resectable
    • localized tumor extension into endothoracic fascia and / or
    • localized non-transmural involvement of pericardium and / or
    • localized extension into mediastinal fat
  • T4
    • unresectable
    • multiple foci of extension into chest wall +/- rib destruction and/or
    • extension through diaphragm into peritoneum and / or
    • extension into contralateral pleura and / or
    • extension into mediastinal organs and / or
    • extension through pericardium +/- direct extension into heart
N - Nodes
  • Nx: nodes cannot be assessed
  • N0: no evidence of nodal involvement
  • N1: ipsilateral bronchopulmonary or hilar nodal involvement
  • N2: subcarinal or ipsilateral mediastinal / internal mammary nodes
  • N3: contralateral mediastinal / internal mammary nodes,or ipsilateral / contralateral supraclavicular nodes
M - Metastases
  • M0: no evidence of metastases
  • M1: distant metastases present

NB: The MX category is no longer used, it was removed in the 6th edition of the TNM system, if presence of metastases is not known the cancer is assigned M0 3.

Stage groupings

  • Stage IA: T1a, N0, M0
  • Stage IB:T1b, N0, M0
  • Stage II: T2, N0, M0
  • Stage III:
    • T1 or 2,  N1 or N2, M0 OR
    • T3, any N, M0
  • Stage IV: any T, any N, M1
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Article information

rID: 8721
System: Chest, Oncology
Section: Staging
Synonyms or Alternate Spellings:
  • Malignant pleural mesothelioma staging
  • Staging of malignant pleural mesothelioma

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Cases and figures

  • Figure 1: mesothelioma - gross pathology
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  • Case 1: contralateral nodes
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  • Case 2
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  • Case 3: T4 with rib erosion
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