Table 1.
TNM classification of cutaneous melanoma (adapted from [1])
| Tumour (T) classification | |
| TX | Primary tumour cannot be assessed (e.g. shave biopsy, regressed primary) |
| Tis | Melanoma in situ |
| T1 | ≤1.00 mm |
| T1a | Without ulceration or level II/III |
| T1b | With ulceration or level IV or V |
| T2 | 1.01–2.00 mm |
| T2a | Without ulceration |
| T2b | With ulceration |
| T3 | 2.01–4.00 mm |
| T3a | Without ulceration |
| T3b | With ulceration |
| T4 | >4.00 mm |
| T4a | Without ulceration |
| T4b | With ulceration |
| Node (N) classification | |
| N1 | One lymph node |
| N1a | Micrometastasesa (clinically occult) |
| N1b | Macrometastasesb (clinically apparent) |
| N2 | Two to three lymph nodes |
| N2a | Micrometastasesa |
| N2b | Macrometastasesb |
| N2c | In-transit met(s)/satellite(s) without metastatic lymph nodes |
| N3 | Four or more lymph nodes, metastatic or matted, or in-transit met(s)/satellite(s) with metastatic lymph node(s) |
| Metastasis (M) classification | |
| M1a | Distant skin, subcutaneous or lymph node metastases, normal LDH |
| M1b | Lung metastases, normal LDH |
| M1c | All other visceral metastases, normal LDH; any distant metastases, elevated LDH |
a
Micrometastases are diagnosed after elective or sentinel lymphadenectomy.
b
Macrometastases are clinically detectable lymph node metastases confirmed by therapeutic lymphadenectomy, or lymph node metastases exhibiting gross extracapsular extension.