The Nuts and Bolts of Head and Neck Tumor
Evaluation
Colin McKnight, Kelly Malloy, Amanda Corey, Ashok Srinivasan
Presentation Number: eEdE-126
Disclosures
NONE
Purpose
To review the key imaging features that are
crucial to patient management as discussed
in head and neck tumor boards.
Approach
Various teaching points are critical to the radiologist’s ability to
provide useful and relevant insight into the pertinent imaging
findings in a head and neck tumor board case.
Topics covered include:
-Lymph nodal stations in the neck
-Accepted ranges for normal size in neck lymph nodes at different levels
-When is a lymph node morphologically abnormal?
-Where to look for the ‘unknown primary’
-What are ‘orphan’ lymph nodes?
-How is carotid artery encasement determined?
-Importance of TNM staging
Discussion
Lymph nodal stations in the neck:
How to divide the neck into different lymph nodal stations
Level I: All nodes above the
hyoid bone, below the mylohyoid
muscle, and anterior to a line
drawn through the posterior
edge of the submandibular
gland.
Level IA: Lie between the medial
margins of the anterior bellies of
the digastric muscles.
Level IB: Lie posterior and
lateral to the medial edge of the
anterior belly of the digastric
muscle, and anterior to a line
drawn between the posterior
surface of the submandibular
glands.
IA
I
I
II
II
V
V
IB
Discussion
Lymph nodal stations in the neck:
How to divide the neck into different lymph nodal stations
Level II: Lie from the skull base, at
the lower level of the bony margin
of the jugular fossa, to the level of
the lower body of the hyoid bone.
Level II nodes lie anterior to a line
drawn through the posterior edge
of the sternocleidomastoid muscle
and posterior to a line through the
posterior edge of the
submandibular gland.
Level IIA: Lie anterior, lateral, or
medial to the jugular vein; or lie
posterior to the internal jugular
vein and are inseparable from the
vein.
Level IIB: Lie posterior to the
internal jugular vein and have a fat
plane separating the nodes and
the vein.
I
I
II
II
V
V
IIA
IIB
Discussion
Lymph nodal stations in the neck:
How to divide the neck into different lymph nodal stations
Level III: Lie between
the level of the lower
body of the hyoid bone
and the lower margin of
the cricoid cartilage
arch, anterior to the
posterior edge of the
sternocleidomastoid
muscle and lateral to
the common/internal
carotid artery.
II
VI
III
III
IV
V
Discussion
Lymph nodal stations in the neck:
How to divide the neck into different lymph nodal stations
Level IV: Lie between the
level of the lower margin
of the cricoid cartilage
arch and the level of the
clavicle. These are
located anterior to the
posterior edge of the
stenocleidomastoid
muscle and the
posterolateral edge of the
anterior scalene muscle
and are located lateral to
the common carotid
artery.
II
VI
IV
III
IV
V
Discussion
Lymph nodal stations in the neck:
How to divide the neck into different lymph nodal stations
VI
Level V: Extend from the skull base
to the level of the clavicle.
III
Level VA: Lie between the levels of
the skull base and the bottom of the
cricoid arch. These nodes are
situated posterior to a transverse line
drawn on each axial scan through
the posterior edge of the
sternocleidomastoid muscle.
Level VB: Lie between the axial level
of the bottom of the cricoid arch and
the level of the clavicle. Level VB
nodes lie posterior and lateral to an
oblique line through the posterior
edge of the sternocleidomastoid
muscle and the posterolateral edge
of the anterior scalene muscle.
V
VI
IV
V
Discussion
Lymph nodal stations in the neck:
How to divide the neck into different lymph nodal stations
VI
IV
VI
III
V
V
Level VI: Lie inferior to the lower body of the hyoid bone, superior to the
top of the manubrium, and between the medial margins of the left and
right common carotid arteries or the internal carotid arteries.
Discussion
Lymph nodal stations in the neck:
How to divide the neck into different lymph nodal stations
VII
Level VII: Lie caudal to the top of
the manubrium in the superior
mediastinum, between the
medial margins of the left and
right common carotid arteries.
These nodes extend caudally to
the level of the innominate vein.
Discussion
Accepted ranges for normal size in neck lymph nodes at
different levels:
-Nodal size criteria can be used when nodes are homogenous
and clearly delineated.
-Upper limit for short axis is 11 mm for jugulodigastric lymph
nodes and 10 mm for all other nodes.
-Upper limit for greatest nodal diameter is 1.5 cm for
jugulodigastric, submandibular and submental nodes, and 1
cm for all other nodes.
-Retropharyngeal node <8mm
AJR 1992 158(5):961-969
Discussion
Accepted ranges for normal size in neck lymph nodes at
different levels:
There is an error rate of ≈ 10 - 20% if using size criteria
alone.
The long to short axis ratio has also been proposed to help
evaluate enlarged nodes in the setting of head and neck SCC.
When nodes have a ratio of >2 (ie long and flat) 95% are
benign. When the ratio is less than 2 (i.e. rounder) then a
similar proportion where malignant.
AJR 1992 158(5):961-969
Discussion
When is a lymph node morphologically abnormal?
Rounded
Low density or cystic
(long-short axis ratio <2)
(internal low attenuation
without thick rim)
Discussion
When is a lymph node morphologically abnormal?
Necrotic
Internal low T1 signal with
peripheral thick rim of
enhancement
Extracapsular spread
Pericapsular infiltration implies
worse prognosis
Calcified
E.g., papillary thyroid cancer
metastases, tuberculosis
Discussion
Where to look for the ‘Unknown Primary’:
Metastatic lymph node
Where is the primary tumor?
Discussion
Where to look for the ‘Unknown Primary’:
Look at:
1. Nasopharynx
2. Oropharynx –
(Base of tongue/palatine tonsil)
3. Supraglottic larynx
4. Pyriform sinus
5. Thyroid gland
Occasionally none is seen on
CT. Next step…
PET CT
Primary SCC in palatine tonsillar fossa
Discussion
What are ‘Orphan’ Lymph Nodes?
Lymph nodes in the face and retropharyngeal region
that do not fit into the nodal stations from I-VII
With permission from Radiology 1993; 188(3):695-700.
Discussion
Zygomatic group lymph nodes:
T2
Recurrent SCC in right cheek
T1 Post
Discussion
Parotid space mass. Where are the nodes?
While the retropharyngeal lymph node is apparent on the
T2W image, it is easier to appreciate on the diffusion image
Discussion
One more:
Zygomatic lymph node
Discussion
-Do not forget retropharyngeal
lymph nodes.
-These are probably the most
commonly missed lymph nodes
in the neck
-Look for asymmetry, as well as
displacement of the carotid artery
Discussion
How is carotid encasement determined?
0
Shows 360 involvement
suggestive of encasement
-Determined by calculating degree of
circumferential contact around the carotid
artery by tumor
>270 degrees considered threshold for
encasement
-
Makes the tumor inoperable
Increases risk of carotid blowout
Discussion
Importance of TNM staging:
1. Dictates prognosis
2. Treatment is based on staging
T1 – T2: Single modality: surgery vs radiation therapy
T3 – T4: Combination of both
T4: Can be locally advanced, may not do surgery
Discussion
Importance of TNM staging:
Laryngeal Cancer:
Discussion
Importance of TNM staging:
Laryngeal Cancer:
-Invades paraglottic fat
-Was clinically staged as T2
-Upstaged to T3 based on CT
Normal
Effaced
paraglottic fat
paraglottic fat
Discussion
Importance of TNM staging:
Subglottic
involvement
-Lesion involves supraglottis, glottis, subglottis
-Lesion is transglottic
-While this remains T3, the surgical approach is
changed
Discussion
Nasopharyngeal cancer staging:
Discussion
Nasopharyngeal cancer staging:
-Invasion of the medial pterygoid: Upstaged to T4 based on imaging
-Also, there is an involved retropharyngeal lymph node
-Skull base invasion, if present, would reflect T3 disease
Discussion
Nasopharyngeal cancer staging:
-Invasion of longus colli muscle: While not in TNM staging, implies worse prognosis
-Intracranial extension would qualify as T4 disease
Discussion
Squamous cell cancer staging:
Invasion of the genioglossus and hyoglossus:
Extrinsic tongue muscle invasion is T4 disease
MRI Confirms invasion
Discussion
Squamous cell cancer staging:
Another patient with invasion of posterior genioglossus indicating T4
disease; the normal muscle on the left is depicted as well
Discussion
Squamous cell cancer staging:
Normal fat plane of separation
Patient with pyriform sinus cancer shows loss of fat planes on CT with the
prevertebral muscle. If truly involved, this would be T4 disease.
MRI is a better modality for making this assessment and shows no convincing
extension into the muscles. At surgery, the muscle was free from tumor.
Discussion
Remember Perineural Spread
Right Parotid acinic cell CA with perineural spread
along the facial nerve involving multiple segments.
The genu of the facial nerve
…And the IAC
Note anterior spread from genu to involve the greater superfical petrosal nerve
that reached up to the pterygopalatine fossa and also retrogradely involve the maxillary N.
Discussion
Utility of fat suppression imaging:

Separating fatty atrophy from tumor

Increased conspicuity of primary tumor borders after
contrast administration

“Revealing” small lesions including perineural spread
surrounded by fat
Discussion
Fatty denervation versus tumor
Fat sat imaging helpful
because fat is abundant
in the neck.
Fat sat imaging reveals fatty denervation in the right tongue from
hypoglossal nerve palsy. Clinically diagnosed as bulky tongue lesion
Discussion
T1 + Without Fat saturation
T1 + With Fat saturation
Right neck SCC
Perineural spread along V3 nerve is seen much more
conspicuously with fat saturation (Sometimes subtle
enhancement such as this can be seen only after fat saturation)
Summary
Knowing the imaging pearls and pitfalls in head and
neck tumors is crucial to making a difference to patient
management
Contact: cmcknig@med.umich.edu
Bibliography
1. Som PM, Curtin HD, Mancuso AA. Imaging-based nodal classification for
evaluation of neck metastatic adenopathy. AJR 2000; 174(3):837-844.
2. Som PM. Detection of metastasis in cervical lymph nodes: CT and MRI
criteria and differential diagnosis. AJR 1992; 158(5):961-969.
3. Tart RP, Mukherji SK, Avio AJ, Stringer SP, Mancuso AA. Facial lymph
nodes: normal and abnormal CT appearance. Radiology 1993; 188(3):695700.