A3.
M stage
| M stage | Staging criteria | |
| Anatomic site | LDH level | |
| AJCC, American Joint Committee on Cancer; SLN, sentinel lymph node; CNS, central nervous system; LDH, lactate dehydrogenase. | ||
| M0 | No evidence of distant metastasis | Not applicable |
| M1 | Evidence of distant metastasis | See below |
| M1a | Distant metastasis to skin, soft tissue including muscle, and/or nonregional lymph node | Not recorded or unspecified |
| M1a (0) | Not elevated | |
| M1a (1) | Elevated | |
| M1b | Distant metastasis to lung with or without M1a sites of disease | Not recorded or unspecified |
| M1b (0) | Not elevated | |
| M1b (1) | Elevated | |
| M1c | Distant metastasis to non-CNS visceral sites with or without M1a or M1b sites of disease | Not recorded or unspecified |
| M1c (0) | Not elevated | |
| M1(1) | Elevated | |
| M1d | Distant metastasis to CNS with or without M1a, M1b, or M1c sites of disease | Not recorded or unspecified |
| M1d (0) | Not elevated | |
| M1d (1) | Elevated | |