Thymoma Staging
- There is no universally accepted staging scheme for thymomas
- Staging is best discussed in the report comment and not simply reported as a score
TNM for thymomas has been proposed (based on Masaoka scheme):
| pT | |
|---|---|
| pT1 | Completely encapsulated |
| pT2 | Invades through capsule into fat or normal thymus, but not through pleura or pericardium (may be adherent) or into adjacent organs |
| pT3 | Invades through pleura or pericardium or into adjacent organs (great vessels, lung) |
| pT4 | Pleural or pericardial implants |
| pN | |
| pN1 | Metastasis only to anterior mediastinal nodes |
| pN2 | Metastasis to other intrathoracic nodes |
| pN3 | Metastasis to extrathoracic nodes |
| pM | |
| pM1 | With distant metastases |
- From Tsuchiya et al. Pathol Int 1994; 44:506
- There is no significant difference in disease free or overall survivall between pT1 and pT2 thymomas (Gupta et al. Arch Pathol Lab Med. 2008 Jun;132(6):926-30.)
- They suggested collapsing pT1 and pT2 into one but unfortunately did not actually propose a staging system
Moran (2012) has proposed a system that reflects the indolent nature of completely resected pT1 and pT2 thymomas better than does the Masaoka based TNM system above
| Stage | Features |
|---|---|
| 0 | Completely encapsulated |
| 1 | Invasive into perithymic fat |
| 2 | Direct invasion into A) Innominate vein, mediastinal pleura, lung B) Pericardium C) Great vessels, heart |
| 3 | Metastatic disease A) Intrathoracic structures, diaphragm, lymph nodes B) Extrathoracic invasion |
No provision was made for pleural or pericardial dissemination
