Masaoka-Koga Staging (Thymoma)
Masaoka-Koga staging of thymic epithelial tumors (thymoma): the most advanced finding sets the stage.
Open the calculator → Runs in your browser. Data leaves only if you deliberately send a problem report from the interactive tool.
Example
- Macroscopic invasion into surrounding fat
- Yes
Result: Masaoka-Koga stage IIb
The tool opens with these values already filled in. Replace them with your own.
What the result means
- Stages
- I completely encapsulated; IIa microscopic transcapsular invasion; IIb macroscopic fat invasion or gross pleural/pericardial adherence; III macroscopic invasion into a neighboring organ.
- Stage IV
- IVa pleural or pericardial dissemination; IVb lymphogenous or hematogenous (nodal/distant) metastasis. The most advanced finding sets the stage; Stage III is not subdivided.
What you enter
- Microscopic transcapsular invasion (through the capsule) — Stage IIa
- Macroscopic invasion into surrounding fat, or gross adherence to (not through) pleura/pericardium — Stage IIb
- Macroscopic invasion into a neighboring organ (pericardium, great vessel, lung) — Stage III
- Pleural or pericardial dissemination (separate implant nodules) — Stage IVa
- Lymphogenous or hematogenous (nodal/distant) metastasis — Stage IVb
How this is calculated
Koga K, Matsuno Y, Noguchi M, et al. A review of 79 thymomas: modification of staging system and reappraisal of conventional division into invasive and non-invasive thymoma. Pathol Int. 1994;44(5):359-367. (Terms clarified: Detterbeck FC, et al. J Thorac Oncol. 2011;6(7 Suppl 3):S1710-S1716.) Read the source ↗
A reference and educational tool. Not medical, legal, or financial advice, and not a substitute for clinician judgment.