Part of Cancer staging guidance sheets
Unknown primary - cervical nodes (ICD10 C77.0)
Introduction
This is the data sheet for TNM 9th edition staging of unknown primary - cervical nodes (ICD10 C77.0)
For more detailed information regarding TNM staging, please see pages 43-47 of the UICC TNM 9 book.
Stage groupings
Rules for classification
There should be histological confirmation of squamous cell carcinoma with lymph node metastases but without an identified primary carcinoma. Histological methods should be used to identify EBV and HPV/p16-associated tumours. If there is evidence of EBV, the nasopharyngeal classification is applied. If there is evidence of HPV and/or positive immunohistochemistry p16 overexpression, the p16-positive oropharyngeal classification is applied.
EBV negative and HPV independent or unknown
|
Stage Group |
T stage |
N stage |
M stage |
|---|---|---|---|
|
Stage III |
T0 |
N1 |
M0 |
|
Stage IVA |
T0 |
N2 |
M0 |
|
Stage IVB |
T0 |
N3 |
M0 |
|
Stage IVC |
T0 |
N1, N2, N3 |
M1 |
HPV associated
Clinical
|
Stage Group |
T stage |
N stage |
M stage |
|---|---|---|---|
|
Stage I |
T0 |
N1 |
M0 |
|
Stage II |
T0 |
N2 |
M0 |
|
Stage III |
T0 |
N3 |
M0 |
|
Stage IV |
T0 |
N1, N2, N3 |
M1 |
Pathological
|
Stage Group |
T stage |
N stage |
M stage |
|---|---|---|---|
|
Stage I |
T0 |
N1 |
M0 |
|
Stage II |
T0 |
N2, N3 |
M0 |
|
Stage IV |
T0 |
N1, N2 |
M1 |
EBV positive
|
Stage Group |
T stage |
N stage |
M stage |
|---|---|---|---|
|
Stage I |
T0 |
N1 |
M0 |
|
Stage II |
T0 |
N2 |
M0 |
|
Stage III |
T0 |
N3 |
M0 |
|
Stage IVa |
T0 |
N1, N2, N3 |
M1a |
|
Stage IVb |
T0 |
N1, N2, N3 |
M1b |
TNM clinical classification
EBV negative and HPV independent or unknown
T - primary tumour
|
T value |
Description |
|---|---|
|
cT0 |
No evidence of primary tumour |
N - regional lymph nodes
|
N value |
Description |
|---|---|
|
cN1 |
Metastasis in a single ipsilateral lymph node, 3 cm or less in greatest dimension without clinical extranodal extension |
|
cN2 |
Metastasis described as: cN2a – Metastasis in a single ipsilateral lymph node, more than 3 cm but not more than 6 cm in greatest dimension, without clinical extranodal extension. cN2b – Metastasis in multiple ipsilateral lymph nodes, none more than 6 cm in greatest dimension, without clinical extranodal extension. cN2c – Metastasis in bilateral lymph nodes, none more than 6 cm in greatest dimension, without clinical extranodal extension |
|
cN3a |
Metastasis in a lymph node more than 6 cm in greatest dimension, without clinical extranodal extension. |
|
cN3b |
Metastasis in a single or multiple lymph nodes with clinical extranodal extension*. |
Note
* Clinical extranodal extension is defined as the presence of skin involvement or soft tissue invasion with deep fixation to underlying muscle or adjacent anatomical structures or clinical signs of nerve involvement. Imaging is becoming a standard method of detecting unequivocal extranodal extension.
Midline nodes are considered ipsilateral nodes
M - distant metastasis
|
M value |
Description |
|---|---|
|
cM0 |
No distant metastasis |
|
cM1 |
Distant metastasis |
TNM pathological classification
pN - regional lymph nodes
Histological examination of a selective neck dissection specimen should ordinarily include six or more lymph nodes. Histological examination of a radical or modified radical neck dissection specimen should ordinarily include 15 or more lymph nodes
|
pN value |
Description |
|---|---|
|
pN1 |
Metastasis in a single lymph node, 3 cm or less in greatest dimension without pathological extranodal extension |
|
pN2 |
Metastasis described as: pN2a – Metastasis in a single lymph node, 3 cm or less in greatest dimension with pathological extranodal extension* or more than 3 cm but not more than 6 cm in greatest dimension, without pathological extranodal extension. pN2b – Metastasis in multiple ipsilateral lymph nodes, none more than 6 cm in greatest dimension, without pathological extranodal extension. pN2c – Metastasis in bilateral lymph nodes, none more than 6 cm in greatest dimension, without pathological extranodal extension. |
|
pN3a |
Metastasis in a lymph node more than 6 cm in greatest dimension, without pathological extranodal extension. |
|
pN3b |
Metastasis in a lymph node more than 3 cm in greatest dimension with pathological extranodal extension* or multiple ipsilateral, or any contralateral, or bilateral node(s) with pathological extranodal extension* |
Note:
* Pathological extranodal extension (pENE) should only be diagnosed when tumour that is present within the confines of a lymph node definitively transgresses through the entire thickness of the lymph node capsule into the surrounding connective tissue, with or without stromal reaction.
A soft tissue deposit should be considered as at least one lymph node with extranodal extension if it occurs at a site where a regional lymph node would be expected
TNM clinical classification
HPV associated
T - primary tumour
|
T value |
Description |
|---|---|
|
cT0 |
No evidence of primary tumour |
N - Regional lymph nodes
|
N value |
Description |
|---|---|
|
cNX |
Regional lymph node cannot be assessed |
|
cN0 |
No regional lymph node metastasis |
|
cN1 |
Metastasis in ipsilateral lymph node(s), all 6cm or less in greatest dimension, without unequivocal imaging-detected and/or clinical extranodal extension |
|
cN2 |
Metastasis in ipsilateral lymph node(s), all 6cm or less in greatest dimension, with unequivocal imaging-detected and/or clinical extranodal extension* OR contralateral or bilateral metastasis in lymph node(s), all 6cm or less in greatest dimension, without unequivocal imaging-detected and/or clinical extranodal extension. |
|
cN3 |
Metastasis in lymph node(s), greater than 6cm in greatest dimension OR contralateral or bilateral metastasis in lymph node(s), with unequivocal imaging-detected and/or clinical extranodal extension* |
Note
*Imaging-detected extranodal extension (iENE) on appropriate morphological imaging refers to unequivocal radiologic signs of tumour invasion through the capsule of a lymph node into either perinodal fat or adjacent tissues (e.g. skin, muscle or neurovascular structures) or a coalescent nodal mass, which comprises ≥2 adjacent lymph nodes with loss of their intervening tissue planes and capsules to merge into a single indivisible structure.
Clinical extranodal extension is defined as per Oral Cavity and Mucosal Lip.
Midline nodes are considered ipsilateral nodes
TNM pathological classification
HPV associated
T - primary tumour
|
T value |
Description |
|---|---|
|
T0 |
No evidence of primary tumour |
pN - regional lymph nodes
|
pN value |
Description |
|---|---|
|
pNX |
Regional lymph nodes cannot be assessed |
|
pN0 |
No regional lymph node metastasis |
|
pN1 |
Metastasis in 1-4 lymph nodes without definitive pathologic extranodal extension pN1a – Metastasis in 1 lymph node without definitive pathological extranodal extension pN1b - Metastasis in 2-4 lymph nodes without definitive pathological extranodal extension |
|
pN2 |
1-4 lymph nodes with definitive pathologic extranodal extension OR metastasis in >4 lymph nodes without definitive pathological extranodal extension |
|
pN3 |
Metastasis in >4 lymph nodes with definitive pathological extranodal extension |
Note
Pathological extranodal extension (pENE) should only be diagnosed when tumour that is present within the confines of a lymph node definitively transgresses through the entire thickness of the lymph node capsule into the surrounding connective tissue, with or without stromal reaction.
A soft tissue deposit should be considered as at least one lymph node with extranodal extension if it occurs at a site where a regional lymph node would be expected.
TNM clinical classification
EVB positive
T - primary tumour
|
T value |
Description |
|---|---|
|
cT0 |
No evidence of primary tumours |
N - regional lymph nodes
|
N value |
Description |
|---|---|
|
cNX |
Regional lymph nodes cannot be assessed |
|
cN0 |
No regional lymph node metastasis |
|
cN1 |
Unilateral metastasis in cervical lymph node(s), and/or unilateral or bilateral metastasis in retropharyngeal lymph nodes, and 6 cm or less in greatest dimension, and above the caudal border of cricoid cartilage, and without advanced clinical/radiological extranodal extension* |
|
cN2 |
Bilateral metastasis in cervical lymph nodes, and 6 cm or less in greatest dimension, and above the caudal border of cricoid cartilage and without advanced clinical/radiological extranodal extension* |
|
cN3 |
Metastasis in cervical lymph node(s) greater than 6 cm in dimension or extension below the caudal border of cricoid cartilage or advanced clinical/radiological extranodal extension* |
Note
*Advanced radiological and/or clinical extranodal extension is unequivocal evidence of tumour invasion into adjacent structures (i.e. skin, muscle, salivary gland and/or neurovascular bundles) identified by appropriate morphological imaging or clinical examination.
Midline nodes are considered ipsilateral nodes.
TNM pathological classification
EBV positive
Histological examination of a selective neck dissection specimen should ordinarily include six or more lymph nodes. Histological examination of a radical or modified radical neck dissection specimen should ordinarily include 15 or more lymph nodes
The pN categories correspond to the nasopharynx cN categories, except that extranodal extension is defined pathologically, and evidence of structural (skin, muscle, salivary gland and/or neurovascular bundles) involvement is required.
M - distant metastasis
|
cM0 |
No distant metastasis |
|---|---|
|
M1 |
Distant Metastasis M1a – 1-3 metastatic lesions M1b - >3 metastatic lesions |
Last edited: 27 January 2026 12:22 pm
