| Skin (T) |
|
| T1 |
Limited patches/plaques (covering <10% of the total skin surface) |
| T1a |
Patches only |
| T1b |
Plaques ± patches |
| T2 |
Generalized patches/plaques (covering ≥10% of the total skin surface) |
| T2a |
Patches only |
| T2b |
Plaques ± patches |
| T3 |
Tumor(s) |
| T4 |
Erythroderma |
| Lymph node (N) |
|
| N0 |
No clinically abnormal peripheral lymph nodes; |
| N1 |
Clinically abnormal peripheral lymph nodes; dermatopathic lymphadenopathy or histopathological involvement by isolated atypical lymphocytes, without alteration of the lymph node architecture |
| N1a |
Negative clone |
| N1b |
Positive clone |
| N2 |
Clinically abnormal peripheral lymph nodes; histopathological involvement by aggregates of atypical lymphocytes, without alteration of the lymph node architecture |
| N2a |
Negative clone |
| N2b |
Positive clone |
| N3 |
Clinically abnormal peripheral lymph nodes; frank histopathological involvement and partial/complete effacement of the lymph node architecture |
| NX |
Clinically abnormal peripheral lymph nodes; without histopathological confirmation |
| Viscera (M) |
|
| M0 |
Without visceral involvement |
| M1 |
With visceral involvement |
| Blood (B) |
|
| B0 |
There are no circulating atypical cells (Sézary cells; or <5% of atypical lymphocytes) |
| B0a |
Negative clone |
| B0b |
Positive clone |
| B1 |
Low tumor load in the blood (≥5% of lymphocytes are Sézary cells, but not B2 cells) |
| B1a |
Negative clone |
| B1b |
Positive clone |
| B2 |
Elevated tumor load in the blood and clonal rearrangement of the TCR (≥1000 Sézary cells/microL. and/or CD4:CD8 ≥ 10, and/or CD4 + CD7 - ≥40%, and/or CD4 + CD26 - ≥30%) |
