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PARAPHARYNGEAL SPACE
Transcervical Approach
e transcervical approach is ideal for small benign lesions independent from the deep lobe
of parotid.
e procedure is performed under a general anaesthetic with a nasotracheal tube, which
allows an extra centimetre of anterior distraction of the mandible. A skin crease incision
5 cm below the mandible protects the marginal mandibular branch of the facial nerve. e
platysma is divided and the fascia of the submandibular gland is raised with the superior ap
to protect the facial nerve. e submandibular gland can be mobilized or excised. e stylomandibular ligament is divided, allowing the mandible to be distracted. e parapharyngeal
space is located between the digastric muscle, the mandible, and the medial pterygoid muscle
insertion on the mandible.
Transcervical–Transparotid Approach
e transcervical–transparotid approach is well suited for lesions arising from the deep lobe
of the parotid gland, for vascular tumours (as it allows access to vessels in the neck), and for
the resection of malignant lesions. e transcervical incision is extended into a modied
Blair’s incision. Parotidectomy increases access to the parapharyngeal space. Management
of the facial nerve is determined by the pre-operative functional status and the histology of
the lesion being excised.
Mandibulotomy
A mandibular osteotomy further improves access and may be necessary for inltrative
malignant lesions and those high in the space and/or involving the skull base. A tracheostomy or overnight intubation may be required to protect the airway. Mandibulotomy can
lead to a longer hospital stay, delay in return to normal nutrition, and additional complications, such as temporomandibular joint dysfunction and malunion.
Transoral Robotic Surgery (TORS)
e advent of robotics and modern endoscopic systems has made the transoral approach
more viable for tumours of the parapharyngeal space.
Technical advantages of TORS include a three-dimensional high-resolution image with
magnication, as well as the tremor ltration and motion scaling that allow delicate
dissection.
e improved angled visual access enables the superior and inferior extents of tumours to be
visualised via a transoral approach.
e ideal indications for TORS parapharyngeal space resection are benign salivary gland
tumours occurring in the pre-styloid compartment, displacing the carotid artery posteriorly
and laterally. ese are the majority of parapharyngeal space tumours. Schwannomas and
other benign neural tumours that are not deforming the carotid artery and not displacing
the carotid artery medially are suitable for resection.
Complications of Surgery
Complications relate to vascular injury, lower cranial nerve injury, tumour spillage, tumour
recurrence and rst bite syndrome. First bite syndrome is thought to be due to loss of sympathetic innervation to the parotid gland, which leads to increased sensitivity of the myoepithelial cells to parasympathetic stimulation.
Further Reading
1. Riat F, Dwivedi RC, Palme C, et al. A systematic review of 1143 parapharyngeal space
tumors reported over 20 years. Oral Oncol 2014; 50(5): 421–430.
2. López F, Suárez C, Vander Poorten V, et al. Contemporary management of primary
parapharyngeal space tumors. Head & Neck 2019; 41: 522–535.
308 Head and Neck
STAGING OF HEAD AND NECK CANCER
61. STAGING OF HEAD AND NECK CANCER
Introduction
Many factors aect the outcome of patients with a malignant head and neck tumour. e
factors relate to the tumour, the host, and management. Staging of head and neck cancer is a
system designed to express the relative severity, or extent, of the disease. It is meant to facilitate an estimation of prognosis and to provide useful information for treatment decisions.
General Rules for Staging
e TNM system is based on three components:
T: extent of the primary tumour
•
N: absence or presence and extent of regional lymph node metastases
•
M: absence or presence of distant metastases
•
e ve major sites of the head and neck (oral cavity, oropharynx, larynx, hypopharynx,
and paranasal sinuses) share the same TNM system. Dierent systems are used for the nasopharynx and thyroid (see Head and Neck Endocrine section), because they are suciently
dierent with respect to risk factors, behaviour, and treatment.
Histopathological Grading
e histological grading of squamous cell carcinoma represents estimation by the pathologist of the expected biological behaviour of the neoplasm. e grades are:
GX: Grade of dierentiation cannot be assessed
•
G1: Well-dierentiated
•
G2: Moderately dierentiated
•
G3: Poorly dierentiated
•
G4: Undierentiated
•
e pathological TNM classication is represented by pT, pN, and pM. e extent of the
tumour in terms of the location and level of the lymph nodes should be documented. In addition, the number of nodes that contain tumour and the presence or absence of extranodal
extension of the tumour should be recorded.
Stage Grouping
A tumour w ith four degrees of T, three degrees of N, and two degrees of M will have 24 potential TNM categories. erefore, it has been felt necessary to condense the categories into a
convenient number of TNM stage groups (Table 61.1). e grouping adopted is designed to
Table 61.1 TNM stage grouping
Stage 0 Tis N0 M0
Stage I T1 N0 M0
Stage II T2 N0 M0
Stage III T1, T2 N1 M0
T3 N0, N1 M0
Stage IVA T1, T2, T3 N2 M0
T4a N0, N1, N2 M0
Stage IVB Any T N3 M0
T4b Any N M0
Stage IVC Any T Any N M1
Head and Neck 309
STAGING OF HEAD AND NECK CANCER
Table 61.2 Stage grouping of human papillomavirus (HPV)-related (p16-positive) oropharyngeal
cancer
Stage I T1, T2 N0, N1 M0
Stage II T1, T2 N2 M0
T3 N0, N1, N2 M0
Stage III T1-T3 N3 M0
T4 Any N M0
Stage IV Any T Any N M1
Table 61.3 Stage grouping for nasopharyngeal cancer
Stage I T1 N0 M0
Stage II T1 N1 M0
T2 N0-1 M0
Stage III T1-2 N2 M0
T3 N0-2 M0
Stage IVA T4 N0-2 M0
Stage IVB Any T N3 M0
Stage IVC Any T Any N M1
ensure, as far as possible, that each group is more or less homogeneous with respect to survival. Carcinoma in situ is categorized as stage 0, cases with distant metastases as stage IV.
e exception to this grouping system is p16-positive oropharyngeal and nasopharyngeal
cancers (Tables 61.2 and 61.3).
Method of Staging
Computed tomography (CT) and magnetic resonance imaging (MRI) are now established
as the mainstay investigations in the pre-operative workup of patients with head and neck
cancer. Scans to evaluate the primary site should be performed prior to biopsy to avoid the
eect of upstaging from the oedema caused by biopsy trauma.
Endoscopy and biopsy should be performed by a senior surgeon and should include a description and photographic documentation or diagrammatic representation. Panendoscopy is
recommended only for symptomatic patients or patients with primary tumours known to
have a signicant risk of a second (synchronous) primary tumour.
e cTNM classication, based on examination, imaging, endoscopy, and biopsy, should be
clearly documented in the case le only when all the staging information (including imaging) is collated.
Tumour Staging
Lip and Oral Cavity
e oral cavity extends from the skin-vermilion junction of the lips to the junction of the
hard and so palate above and to the line of the circumvallate papillae below. e anatomic
sites and subsites are as follows:
Lip:
•
External upper lip (vermilion border)
•
External lower lip (vermilion border)
•
Commissures
•
Oral cavity:
•
Buccal mucosa
•
Mucosa of the upper and lower lips
•
310 Head and Neck
STAGING OF HEAD AND NECK CANCER
Table 61.4 TNM clinical classication for lip and oral cavity tumours
T – Primary tumour
T1 Tumour 2 cm or less in greatest dimension and 5 mm or less depth of invasion
T2 Tumour 2 cm or less in greatest dimension and more than 5 mm but no
more than 10 mm depth of invasion or tumour more than 2 cm but not
more than 4 cm in greatest dimension and depth of invasion no more than
10 mm
T3 Tumour more than 4 cm in greatest dimension or more than 10 mm depth of
invasion
T4a Lip: tumour invades through cortical bone, inferior alveolar nerve, oor of
mouth, or skin (chin or nose)
T4a Oral cavity: tumour invades through cortical bone, into deep/extrinsic muscle of
tongue, maxillary sinus, or skin of face
T4b Lip or oral cavity: tumour invades masticator space, pterygoid plates, or skull
base, or encases internal carotid artery
Cheek mucosa
•
Retromolar areas
•
Buck-alveolar sulci, upper and lower (vestibule of mouth)
•
Upper alveolus and gingiva (upper gum)
•
Lower alveolus and gingiva (lower gum)
•
Hard palate
•
Tongue—dorsal surface, lateral borders anterior to vallate papillae (anterior two
•
thirds), and inferior (ventral) surface
Floor of mouth
•
e eighth edition of the staging system recognises the importance of depth of invasion and
this is shown in Table 61.4.
Pharynx
e pharynx is divided into three regions: nasopharynx, oropharynx, and hypopharynx.
e eighth edition staging manual has been divided into three separate entities—nasopharyngeal cancer, HPV-associated (p16-positive) oropharyngeal cancer, and hypopharyngeal
and non-HPV-associated (p16-negative) oropharyngeal cancer—to better reect the variety
of diseases arising in the pharynx.
Each region is subdivided into specic sites as summarized below.
Oropharynx
e oropharynx is the portion of the pharynx extending from the plane of the superior
surface of the so palate to the superior surface of the hyoid bone (or oor of the vallecula).
It includes:
Anterior subsites (glosso-epiglottic area)
•
Base of tongue (posterior to the vallate papillae or posterior third)
•
Vallecula
•
Lateral subsites
•
Lateral wall
•
Ton sil
•
Ton sil lar fo ssa
•
Tonsillar pillar
•
Posterior wall
•
Superior subsites
•
Inferior surface of so palate
•
Uvula
•
1, 2
Head and Neck 311
STAGING OF HEAD AND NECK CANCER
Table 61.5a Oropharyngeal cancer: p16-negative cancers or p16 immunohistochemistry not
performed
T – Primary tumour
T1 Tumour 2 cm or less in greatest dimension
T2 Tumour more than 2 cm but not more than 4 cm in greatest diameter
T3 Tumour more than 4 cm in greatest dimension or extension to lingual surface of
the epiglottis
T4a Tumour invades any of the following: larynx, deep extrinsic muscles of tongue
(genioglossus, hyoglossus, palatoglossus, and styloglossus), medial pterygoid,
or mandible and hard palate.
T4b Tumour invades any of the following: lateral pterygoid muscle, pterygoid plates,
lateral nasopharynx, or skull base, or it encases the carotid artery.
Table 61.5b Oropharyngeal cancer: p16-positive cancers
T – Primary tumour
T1 Tumour 2 cm or less in greatest dimension
T2 Tumour more than 2 cm but not more than 4 cm in greatest diameter
T3 Tumour more than 4 cm in greatest dimension or extension to lingual surface of
the epiglottis
T4 Tumour invades any of the following: larynx, deep extrinsic muscles of tongue
(genioglossus, hyoglossus, palatoglossus, and styloglossus), medial pterygoid,
mandible and hard palate, lateral pterygoid muscle, pterygoid plates, lateral
nasopharynx, or skull base, or it encases the carotid artery
e classication of p16-positive and p-16 negative oropharyngeal tumours is shown in
Tables 61.5a and 61.5b.
Nasopharynx
e nasopharynx begins anteriorly at the posterior choana and extends along the plane of
the airway to the level of the free border of the so palate. It includes:
Superior wall
•
Posterior wall: from the level of the junction of the hard and so palates to the superior
•
wall
Lateral wall: including the fossa of Rosenmüller
•
Floor: superior surface of the so palate
•
e classication of nasopharyngeal tumours is shown in Table 61.6.
Hypopharynx
e hypopharynx extends from the superior border of the hyoid bone to the lower border of
the cricoid cartilage. It includes the piriform sinuses, the postcricoid area, and the lateral and
posterior pharyngeal walls.
e postcricoid area (pharyngo-oesophageal junction) extends from the level of the
•
arytenoid cartilages and connecting folds to the inferior border of the cricoid cartilage, thus forming the anterior wall of the hypopharynx.
Piriform sinus extends from the pharyngo-epiglottic fold to the upper end of the
•
oesophagus. It is bounded laterally by the thyroid cartilage and medially by the
hypopharyngeal surface of the aryepiglottic fold and the arytenoid and cricoid
cartilages.
312 Head and Neck
STAGING OF HEAD AND NECK CANCER
Table 61.6 Nasopharyngeal tumours
T – Primary tumour
T1 Tumour is conned to nasopharynx or extends to oropharynx and/or nasal cavity
without parapharyngeal involvement
T2 Tumour extends to parapharyngeal space and/or has inltration of the medial
pterygoid, lateral pterygoid, and/or prevertebral muscles
T3 Tumour invades bony structures of skull base, cervical vertebra, pterygoid
structures, and/or paranasal sinuses
T4 Tumour has intracranial extension and/or involvement of cranial nerves,
hypopharynx, orbit, or parotid gland, and/or inltration beyond the lateral
surface of the lateral pterygoid muscle
Note: Parapharyngeal extension denotes posterolateral inltration of tumour beyond the pharyngo-
basilar fascia.
Posterior pharyngeal wall extends from the superior level of the hyoid bone (or oor
•
of the vallecula) to the level of the inferior border of the cricoid cartilage and from the
apex of one piriform sinus to the other.
e current staging for hypopharyngeal tumours is summarised in Table 61.7.
Larynx
e anatomical sites and subsites of the larynx are:
Supraglottis:
•
Suprahyoid epiglottis (including tip and lingual [anterior] and laryngeal
•
surfaces)
Aryepiglottic fold, laryngeal aspect
•
Arytenoid
•
Infrahyoid epiglottis
•
Ventricular bands (false cords)
•
Glottis:
•
Vocal cords
•
Anterior commissure
•
Posterior commissure
•
Subglottis
•
Tables 61.8, 61.9, and 61.10 detail the T stages for the various laryngeal cancer sites.
Table 61.7 Hypopharyngeal tumours
T – Primary tumour
T1 Tumour is limited to one subsite of hypopharynx and is 2 cm or less in greatest
dimension
T2 Tumour invades more than one subsite of hypopharynx or an adjacent site, or
measures 2–4 cm in greatest dimension, without xation of hemilarynx
T3 Tumour measures >4 cm in greatest dimension, or involves xation of hemilarynx or
extension to oesophagus
T4a Tumour invades any of the following: thyroid/cricoid cartilage, hyoid bone, thyroid
T4b Tumour invades prevertebral fascia, encases carotid artery, or invades mediastinal
Note: Central compartment soft tissue includes prelaryngeal strap muscles and subcutaneous fat.
gland, oesophagus, or central compartment soft tissue
structures
Head and Neck 313
STAGING OF HEAD AND NECK CANCER
Table 61.8 Supraglottic tumour stages
T – Primary tumour
T1 Tumour is limited to one subsite of supraglottis with normal vocal cord mobility
T2 Tumour invades mucosa of more than one adjacent subsite of supraglottis or glottis or
region outside the supraglottis (e.g. mucosa of base of tongue, vallecula, medial wall of
piriform sinus) without xation of the larynx
T3 Tumour is limited to larynx with vocal cord xation and/or invades any of the following:
postcricoid area, pre-epiglottic tissues, or paraglottic space and/or with minor thyroid
cartilage erosion (e.g. inner cortex)
T4a Tumour invades through thyroid cartilage and/or invades tissues beyond the larynx, e.g.
trachea, soft tissues of the neck, including deep/extrinsic muscles of the tongue (genioglossus,
hyoglossus, palatoglossus, and styloglossus), strap muscles, thyroid, and oesophagus
T4b Tumour invades prevertebral space or mediastinal structures or encases carotid artery
Table 61.9 Glottic tumour stages
T – Primary tumour
T1 Tumour is limited to vocal cord(s) (may involve anterior or posterior commissure) with
normal mobility
T1a—tumour is limited to one vocal cord
T1b—tumour involves both vocal cords
T2 Tumour extends to supraglottis and/or subglottis, and/or with impaired vocal cord mobility
T3 Tumour is limited to larynx with vocal cordu xation and/or invades paraglottic space,
and/or with minor thyroid cartilage erosion (inner cortex)
T4a Tumour invades through thyroid cartilage or invades tissues beyond the larynx, e.g.
trachea, soft tissues of neck including deep/extrinsic muscle of tongue (genioglossus,
hyoglossus, palatoglossus and styloglossus), strap muscles, thyroid, and oesophagus
T4b Tumour invades prevertebral space or mediastinal structures or encases carotid artery
Table 61.10 Subglottic tumour stages
T – Primary tumour
T1 Tumour is limited to subglottis
T2 Tumour extends to vocal cord(s) with normal or impaired mobility
T3 Tumour is limited to larynx with vocal cord xation
T4a Tumour invades through cricoid or thyroid cartilage and/or invades tissues beyond the
larynx, e.g. trachea, soft tissues of neck including deep/extrinsic muscle of tongue
(genioglossus, hyoglossus, palatoglossus, and styloglossus), strap muscles, thyroid, and
oesophagus
T4b Tumour invades prevertebral space or mediastinal structures or encases carotid artery
Nasal Cavity and Paranasal Sinuses
e anatomical sites and subsites are:
Nasal cavity:
•
Septum
•
Floor
•
Lateral wall
•
Vest ibule
•
Maxillary sinus
•
Ethmoid sinus
•
Tumour `staging is documented in Tables 61.11 and 61.12.
314 Head and Neck
STAGING OF HEAD AND NECK CANCER
Table 61.11 Maxillary sinus tumours
T – Primary tumour
T1 Tumour is limited to the antral mucosa with no erosion or destruction of bone
T2 Tumour causes bone erosion or destruction, including extension into hard palate and/or
middle nasal meatus, except extension to the posterior wall of maxillary sinus and
pterygoid plates
T3 Tumour invades any of the following: bone of posterior wall of maxillary sinus,
subcutaneous tissues, oor or medial wall of orbit, pterygoid fossa, or ethmoid sinuses
T4a Tumour invades any of the following: anterior orbital contents, skin of cheek, pterygoid
plates, infratemporal fossa, cribriform plate, and sphenoid or frontal sinus.
T4b Tumour invades any of the following: orbital apex, dura, brain, middle cranial fossa,
cranial nerves other than maxillary division of trigeminal nerve, nasopharynx, and clivus
Table 61.12 Nasal cavity and ethmoid sinus tumours
T – Primary tumour
T1 Tumour is restricted to one subsite of nasal cavity or ethmoid sinus without bone erosion
T2 Tumour involves two subsites or extends to involve an adjacent site within the
nasoethmoidal complex, with or without bony invasion
T3 Tumour extends to invade the medial wall or oor of the orbit, maxillary sinus, palate, or
cribriform plate
T4 Tumour invades any of the following: anterior orbital contents, skin of nose or cheek,
minimal extension to anterior cranial fossa, pterygoid plates, and sphenoid or frontal
sinuses
T4b Tumour invades any of the following: orbital apex, dura, brain, middle cranial fossa,
cranial nerves other than maxillary division of trigeminal nerve, nasopharynx, and clivus
Salivary Glands
e staging classication (Table 61.13) applies only to carcinomas of the major salivary
glands. Tumours arising in minor salivary glands (mucus-secreting glands in the lining
membrane of the upper aerodigestive tract) should be staged according to their anatomical
site of origin (e.g. lip). ere should be histological conrmation of the disease. e anatomical sites and subsites are:
Parotid gland
•
Submandibular gland
•
Sublingual gland
•
Unknown Primary
ere should be histological conrmation of squamous cell carcinoma with lymph node
metastases but without an identied primary carcinoma. Current recommended diagnostic
Table 61.13 Salivary gland tumours
T – Primary tumour
T1 Tumour is 2 cm or less in greatest dimension without extraparenchymal extension*
T2 Tumour is more than 2 cm but no more than 4 cm in greatest dimension without
extraparenchymal extension*
T3 Tumour is more than 4 cm and/or with extraparenchymal extension
T4a Tumour invades skin, mandible, ear canal, or facial nerve
T4b Tumour invades base of skull or pterygoid plates or encases carotid artery
*Extraparenchymal extension is clinical or macroscopic evidence of invasion of skin, soft tissues, or
nerve, except those listed under T4a and T4b. Microscopic evidence alone does not constitute
extraparenchymal extension for classication purposes.
Head and Neck 315
STAGING OF HEAD AND NECK CANCER
methods include an early PET CT scan with targeted biopsies based on the ndings. Transoral
laser or robotic excision of the tonsil and tongue base mucosectomy are also recommended
in cases that remain unknown. Histological methods should be used to identify Epstein-Barr
virus (EBV) and HPV/p16-related tumours. If there is evidence of EBV, the nasopharyngeal
classication is applied. If there is evidence of HPV and positive immunohistochemistry p16
overexpression, the p16-positive oropharyngeal classication is applied. One key change from
previous versions of the TNM system is the elimination of the T0 category in sites other than
the nasopharynx, high risk HPB (HR-HPV)–associated oropharyngeal carcinoma (OPC),
and salivary gland cancers (which can be identied by their unique histology). If no primary
lesion can be identied, then the lymph node may have emanated from any mucosal site, so
there is no rationale to support retaining the T0 designation outside of the virally associated
cancers of the oropharynx and nasopharynx.
Skin Carcinoma of the Head and Neck
Head and neck skin cancer is now presented in a separate chapter in the eighth edition of
the American Joint Committee on Cancer (AJCC)/Union for International Cancer Control
(UICC) staging manual. e classication applies to cutaneous carcinomas of the head and
neck region excluding the eyelid (as an anatomical site), Merkel cell carcinoma, and malignant melanoma. e T stage is presented in Table 61.14, and the N stages are the same as
nodal metastases from other sites of the head and neck. e following sites are recognised:
Lip
•
External ear
•
Other and unspecied parts of the face
•
Scalp and neck
•
Malignant Melanoma of the Upper Aerodigestive Tract
e classication in Table 61.15 applies only to mucosal malignant melanomas of the head
and neck region. e regional lymph nodes are staged according to the site in the upper
aerodigestive tract of the tumour. Because malignant melanoma are aggressive tumours,
T1 and T2, are omitted as are stages I and II.
Table 61.14 Head and neck skin cancer
T1 Tumour is 2 cm or less in greatest dimension
T2 Tumour is >2 cm and <4 cm in greatest dimension
T3 Tumour is >4 cm in greatest dimension or has minor bone erosion or perineural
invasion or deep invasion
T4a Tumour has gross cortical bone/marrow extension
T4b Tumour has skull base or axial skeleton invasion including foraminal involvement
and/or vertebral foramen involvement to the epidural space
*Deep invasion is dened as invasion beyond the subcutaneous fat or >6 mm (as measured from
the granular layer of adjacent normal epidermis to the base of the tumour). Perineural invasion for
T3 classication is dened as clinical or radiographic involvement of named nerves without foramen
or skull base invasion or transgression.
Table 61.15 Malignant melanoma of the upper aerodigestive tract
TX Primary tumour cannot be assessed
T0 No evidence of primary tumour
T3 Tumour is limited to the epithelium and/or submucosa (mucosal disease)
T4a Tumour invades deep soft tissue, cartilage, bone, or overlying skin
T4b Tumour invades any of the following: brain, dura, skull base, lower cranial
nerves (IX, X, XI, XII), masticator space, carotid artery, prevertebral space, or
mediastinal structures
*
316 Head and Neck
STAGING OF HEAD AND NECK CANCER
Regional Lymph Nodes
Lymph nodes are described as ipsilateral, bilateral, contralateral, or midline; they may be
single or multiple and are measured by size, number, and anatomical location. Midline nodes
are considered ipsilateral nodes, except with thyroid cancers. Direct extension of the primary tumour into lymph nodes is classied as lymph node metastasis.
Lymph nodes are subdivided into specic anatomical sites and are grouped into seven levels
for ease of description (Table 61.16).
e denitions of the N categories (Table 61.17) are the same for most head and neck sites
(oral cavity, p16-negative pharyngeal carcinoma, laryngeal carcinoma, sinus carcinoma, salivary gland carcinoma). e AJCC/UICC manual’s eighth edition recognises the importance
of extranodal extension (previously called extracapsular spread).
e latest edition of the AJCC/UICC manual has also introduced two separate staging systems
(cTNM and pTNM) for neck metastases of HPV-related (p16-positive) oropharyngeal cancer
(Tables 61.18a and 61.18b). Studies have shown a signicant dierence in outcome based on
the number of pathologically positive lymph nodes, dening two categories: those with 1 to 4
(N1) versus 5 or more (N2) positive nodes. As the number of nodes can only be counted in the
neck dissection specimen, a separate N system based on histological assessment of the neck
dissection specimen has been created (pTNM). Recognizing that lymph node size >6 cm does
not have a prognostic role in surgically treated necks, no pN3 category exists.
Table 61.16 Nomenclature for anatomical sites of lymph nodes
Level I Contains the submental and submandibular triangles, bounded by the posterior belly of
the digastric muscle, the hyoid bone inferiorly, and the body of the mandible superiorly
Level II Contains the upper jugular lymph nodes and extends from the level of the hyoid
bone inferiorly to the skull base superiorly
Level III Contains the middle jugular lymph nodes from the hyoid bone superiorly to the
cricothyroid membrane inferiorly
Level IV Contains the lower jugular lymph nodes from the cricothyroid membrane superiorly
to the clavicle inferiorly
Level V Contains the posterior triangle lymph nodes, bounded by the anterior border of the
trapezius posteriorly, the posterior border of the sternocleidomastoid muscle
anteriorly, and the clavicle inferiorly
Level VI Contains the anterior compartment lymph nodes from the hyoid bone superiorly to
the suprasternal notch inferiorly. On each side, the medial border of the carotid
sheath forms the lateral border
Level VII Contains the lymph nodes inferior to the suprasternal notch in the upper mediastinum
Table 61.17 Clinical N stage
NX Regional lymph nodes cannot be assessed.
N0 No regional lymph node metastasis
N1 Metastasis in a single ipsilateral lymph node, 3 cm or less in greatest dimension
without extranodal extension
N2 N2a—Metastasis in a single ipsilateral lymph node, more than 3 cm but not more
than 6 cm in greatest dimension without extranodal extension
N2b—Metastasis in multiple ipsilateral lymph nodes, none more than 6 cm in
greatest dimension, without extranodal extension
N2c—Metastasis in bilateral or contralateral lymph nodes, none more than 6 cm in
greatest dimension, without extranodal extension
N3a Metastasis in a lymph node more than 6 cm in greatest dimension without
extranodal extension
N3b Metastases in a single or multiple lymph nodes with clinical extranodal extension
Head and Neck 317
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