IMAGING CERVICAL LYMPH NODES

WADE WONG, D.O.


NORMAL ANATOMY

Significant Nodal Groups

Deep lateral cervical.
Submental-submandibular.
Parotid.
Retropharyngeal.
Anterior cervical.

Deep Lateral Cervical Group

A. Internal jugular chain (deep cervical).

B. Spinal accessory chain (posterior triangle).

C. Transverse cervical (supraclavicular).

The highest jugular digastric node near the angle of the mandible is called the "sentinel" node.

The "signal" node is the lowest along the internal jugular chain called the virchow nodes.

If only a virchow node is present, then one should check the abdomen and/or chest for primary source of metastasis.

The internal jugular chain is divided into:

High: Above the hyoid.

Mid: Between hyoid and cricoid.

Low: Below the cricoid.

The internal jugular chain is a common final pathway that receives drainages from parotid, retropharyngeal, and submandibular/submental groups. Drainage from the internal jugular chain is into the subclavian vein and/or internal jugular vein and/or into the right lymphatic duct and thoracic duct.

Spinal accessory (posterior triangle) nodal group receives occipital/mastoid, lateral neck, scalp, nasal pharyngeal sources.

Abnormal spinal accessory nodes may indicate the presence of an early nasal pharyngeal cancer.

Transverse cervical chain receives drainage from deep cervical, supraclavicular, subclavicular, upper chest, anterior lateral neck. Sources. The drainage is the same as for the internal jugular chain.

Submental/Submandibular Chain

Submental nodes receive drainage from adjacent skin, lips, floor of the mouth, and drain to the submandibular nodal group.

Submandibular nodes are extra glandular and receive drainage from anterior face, flow of the mouth, anterior oral cavity, and submental nodal group. Drainage is to the high internal jugular chain.

Parotid Nodal Group

Intra or extra glandular nodes.

Receives drainage from external artery canal, eustachian tube, adjacent skin, buccal mucosa. (skin squamous cell cancer and melanoma frequently metastasize to this group). Drainage is to high internal jugular chain.

Retropharyngeal Nodal Group

Two compartments: Medial and lateral retropharyngeal.

Medial retropharyngeal receives drainage from nasal pharynx and oral pharynx and drains to high internal jugular chain.

Lateral retropharyngeal (nodes of Rouvierre) are located just medial to the internal carotid artery. Drainage is the same as for the medial retropharyngeal nodes.

Early sign of nasal pharyngeal cancer may be presence of abnormal lateral retropharyngeal node in the patient over forty.

Anterior Cervical Nodal Group

Anterior jugular: superficial. Follows the course of the external jugular vein. Receives drainage from skin and muscles of the anterior neck. Drains to the thoracic duct.

Paraesophageal group: Tracheal esophageal groove nodes and delphian node. Abnormal delphian node is often an indicator subglottic laryngeal cancer extension.

This group receives drainages from hypopharynx, larynx, thyroid, and esophagus. Drainage is then to the thoracic duct.

Simplified Nodal Classification

Level 1: Submandibular, submental.

Level 2: Internal jugular from skull base to carotid bifurcation.

Level 3: Internal jugular below carotid bifurcation to omohyoid.

Level 4: Internal jugular below omohyoid.

Level 5: Posterior triangle.

Level 6: Adjacent to thyroid.

Level 7: Tracheal esophageal groove and superior mediastinum.

NODAL PATHOLOGY

Malignant Adenopathy

Is associated with a fifty percent reduction in long term survival.


Abnormal (malignant) Nodes

Size:

Greater than 1.5 centimeters in juglo digastric area (level 1, 2, and 3).

Greater than 1 centimeter elsewhere.

Necrosis: Regardless of size.

Extracapsular spread: Regardless of size.


Staging information is necessary for selection for most appropriate treatment option.

Ten to thirty percent of malignant nodes are clinically undetected on physical examination due to deep location especially in retropharyngeal and high internal jugular chains.

Accuracy of nodal staging CT: Ninety to ninety-five percent. Physical exam seventy-five percent.

Pitfalls of physical exam:

Nodal conglomerates may be mistaken for a single node.

Can't determine extracapsular spread.

Difficult to detect deep nodes.

Clinical Nodal Staging

NX: Not assessable.
N0: No clinically positive nodes.
N1: Single clinically positive ipsilateral node less than or equal to 3 centimeters.
N2: Greater than 3 centimeter, less than 6 centimeter.
N2A: Single, ipsilateral.
N2B: Multiple ipsilateral.
N3: Greater than 6 centimeter.
N3A: Ipsilateral.
N3B: Bilateral.
N3C: Contralateral

Modified AJCC (Harnsberger) Nodal Staging

N0: Less than 1.5 centimeters, no central necrosis.
N1: Single ipsilateral node 15-29 millimeters or less than 15 millimeters with central necrosis.
N2: Ipsilateral 3-6 centimeters.
N2A: Single.
N2B: Multiple.
N3: Greater than 6 centimeters.
N3A: Ipsilateral.
N3B: Bilateral.
N3C: Contralateral.
N3D: Extracapsular.

Extracapsular spread carries a grave prognosis and may be the best indicator of treatment failure.

Signs of Extracapsular Spread

Spiculated margins.

Fatty invasion.

Encasement of vessels.

Accuracy Comparison CT versus MR:

CT = MR for detecting and sizing nodes.

CT better than MR for demonstrating necrosis.

CT better than MR for detecting extracapsular spread.

Nodes from Unknown Primary

Approximately ten percent of patients with abnormal cervical nodes present without obvious primary.
Most common sites for unknown primary:
Nasal Pharynx.
Pyriform Sinus.
Tongue Base.
Tonsillar Crypts.
Thyroid.
Lung.
Knowledge of drainage patterns may help in search for primary.

Probable Source of Nodal Metastasis

Level 1: Oral cavity, submandibular gland.
Level 2: Nasal pharynx, oral pharynx, parotid, superglottic larynx.
Level 3: Oral pharynx, hypopharynx, superglottic larynx.
Level 4: Subglottic larynx, hypopharynx, esophagus, thyroid.
Level 5: Nasal pharynx, oral pharynx.
Level 6 & 7: Thyroid, larynx, lung.
Note: Bilateral nodes are common with cancers of soft pallet, tongue, epiglottice, and nasal pharynx.

Lymphoma

Usually non-Hodgkin's lymphoma: Large nodes, enlargement of Waldeyer's ring, extra lymphatic enlargement of particular glands such as the thyroid.

Hodgkin's lymphoma may be present (25 percent of head & neck lymphoma) particularly if there is also a mediastinal involvement.

Lymphomas can cross fascial planes easily.

Can undergo rapid enlargement.

Differential diagnosis: squamous cell cancer, infectious mononucleosis.

Non-Malignant Adenopathy

Granulomatous disease: TB, sarcoid.
Fungal: cocci.
Cat scratch fever.
Castleman's.
AIDS.
Post radiation changes.

Pitfalls CT/Ultrasound

Inflammatory disease leading to pseudo necrosis with TB or abnormal enlargement with cat scratch, sarcoid.

Post inflammatory fatty infiltration: (These nodes will be oval and low density of fat should not be central).

Tuberculosis

Painless posterior neck mass.

Scrofula: Common in Southeast Asia, (California).

Necrotic nodes particularly in level 5.

Multi-loculated disturbed fat planes, thick rim enhancement.

May calcify following treatment.

Castleman's

Abnormal nodes in chest and head and neck.

Usually non-necrotic but brightly enhanced with contrast.

Infectious Mononucleosis

Multiple large non-necrotic nodes.

Enlargement of Waldeyer's ring.

Appears similar to AIDS, sarcoid, leukemia, lymphoma.

Cat Scratch Fever

Bilateral large nodes including intraparotid nodes.

Uncertain etiology ? viral or ricketsial.

AIDS

Multiple small nodes.

Non-necrotic.

Enlargement of Waldeyer's ring.

Associated lympho epithelial cyst.

REFERENCES

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