Part of Cancer staging guidance sheets
Merkel cell carcinoma of skin (ICD10 C00, C44, C51, C60, 63.2, C80)
Introduction
This is the data sheet for TNM 9th edition staging of the merkel cell carcinoma of skin (ICD10 C00, C44, C51, C60, C63.2, C80)
For more detailed information regarding TNM staging, please see pages 149-150 of the UICC TNM 9 book.
Stage groupings
Clinical stage
|
Stage Group |
T stage |
N stage |
M stage |
|---|---|---|---|
|
Stage 0 |
Tis |
N0 |
M0 |
|
Stage I |
T1 |
N0 |
M0 |
|
Stage IIA |
T2, T3 |
N0 |
M0 |
|
Stage IIB |
T4 |
N0 |
M0 |
|
Stage III |
Any T |
N1, N2, N3 |
M0 |
|
Stage IV |
Any T |
Any N |
M1 |
Pathological stage
| Stage Group | T stage | N stage | M stage |
|---|---|---|---|
|
Stage 0 |
Tis |
N0 |
M0 |
|
Stage I |
T1 |
N0 |
M0 |
|
Stage IIA |
T2, T3 |
N0 |
M0 |
|
Stage IIB |
T4 |
N0 |
M0 |
|
Stage IIIA |
T0 |
N1b |
M0 |
|
|
T1, T2, T3, T4 |
N1a, N1a(sn) |
M0 |
|
Stage IIIB |
T1, T2, T3, T4 |
N1b, N2, N3 |
M0 |
|
Stage IV |
Any T |
Any N |
M1 |
TNM clinical classification
T - primary tumour
|
T value |
Description |
|---|---|
|
cTX |
Primary tumour cannot be assessed |
|
cT0 |
No evidence of primary tumour |
|
cTis |
Carcinoma in situ |
|
cT1 |
Tumour 2 cm or less in greatest dimension |
|
cT2 |
Tumour more than 2 cm but not more than 5 cm in greatest dimension |
|
cT3 |
Tumour more than 5 cm in greatest dimension |
|
cT4 |
Tumour invades deep extradermal structures, i.e., cartilage, skeletal muscle, fascia or bone |
N - regional lymph nodes
|
N value |
Description |
|---|---|
|
cNX |
Regional lymph nodes cannot be assessed |
|
cN0 |
No regional lymph node metastasis |
|
cN1 |
Regional lymph node metastasis |
|
cN2 |
In‐transit metastasis without lymph node metastasis |
|
cN3 |
In‐transit metastasis with lymph node metastasis |
Note:
In‐transit metastasis: a discontinuous tumour distinct from the primary lesion and located between the primary lesion and the draining regional lymph nodes or distal to the primary lesion.
M - distant metastasis
|
M value |
Description |
|---|---|
|
cM0 |
No distant metastasis |
|
cM1 |
Distant metastasis cM1a - Skin, subcutaneous tissues or non‐regional lymph node(s) cM1b - Lung cM1c - Other site(s) |
pTNM pathological classification
pT - primary tumour
The pT category correspond to the cT category.
pN - regional lymph nodes
|
pN value |
Description |
|---|---|
|
pN0 |
Histological examination of a regional lymphadenectomy specimen will ordinarily include 6 or more lymph nodes. If the lymph nodes are negative, but the number ordinarily examined is not met, classify as pN0. |
|
pNX |
Regional lymph nodes cannot be assessed |
|
pN0 |
No regional lymph node metastasis |
|
pN1 |
Regional lymph node metastasis pN1a(sn) - Microscopic metastasis detected on sentinel node biopsy pN1a - Microscopic metastasis detected on node dissection pN1b - Macroscopic metastasis (clinically apparent) |
|
pN2 |
In‐transit metastasis without lymph node metastasis |
|
pN3 |
In‐transit metastasis with lymph node metastasis |
Note:
In‐transit metastasis: a discontinuous tumour distinct from the primary lesion and located between the primary lesion and the draining regional lymph nodes or distal to the primary lesion.
Last edited: 20 January 2026 4:47 pm
