1	KNOW THE NODES: A Review of Cervical Lymph Node Anatomy ASNR 2008 Control number 749, Paper 50 Katrina McGinty MD Rona Woldenberg MD North Shore University Hospital Manhasset, New York
2	Overview I. Discuss current imaging modalities and their role in evaluation of cervical lymph nodes II. Discuss the current system of classification of cervical lymph nodes III. Review the appearance of abnormal nodes in commonly encountered pathology IV. Discuss the implications of abnormal nodes in management of the head and neck cancer patient
3	Classification of cervical lymph nodes Classification of cervical lymph node anatomy was traditionally based on palpation and surgical landmarks As imaging became a more integral part of management in head and neck cancer, an imaging based classification of lymph node anatomy was created to help guide clinical management of these patients Advantages of pretreatment imaging include: Improved detection rates of head and neck cancer Delineation of the presence and extent of disease in nodes beyond the range of physical examination (e.g. retropharyngeal involvement) Aiding in selecting a treatment approach; surgical management versus radiation therapy and/or chemotherapy
4	Imaging techniques Contrast enhanced CT: most common modality Advantages: excellent anatomic detail, quick, good spatial resolution Pitfalls: less sensitive MRI Advantages: more sensitive, more useful when performing a targeted exam Pitfalls: time consuming, motion artifact, cost, smaller target area, artifact from metallic objects (aneurysm clips, etc) Ultrasound Generally used as a targeted examination for guiding procedures (e.g. biopsies) rather than screening method Advantages: very sensitive for distinguishing normal fatty hilum from tumor invasion and normal versus abnormal flow Disadvantages: operator dependent PET: More commonly used for post-treatment surveillance and to evaluate response to therapy
5	Overview of Nodal Groups Nodal classification by level Level I - VII based on anatomic landmarks Anatomically named groups Parotid Occipital Retropharyngeal Mastoid/Postauricular Supraclavicular
6	Classification of nodes by level Group IA and IB: Submental and Submandibular nodes Groups II, III and IV: Internal jugular or deep cervical nodes; superior, middle and inferior groups Group V: Posterior Triangle nodes Group VI: Anteriorly, midline suprasternal nodes Group VII: Retrosternal nodes
7	Level I Nodes Borders Inferior: Hyoid bone Superior: Mylohyoid muscle Posterior: Posterior edge of the submandibular gland IA: Submental: between the anterior bellies of the digastrics IB: Submandibular: posterior and lateral to the medial edge of the anterior bellies of the digastrics Drainage IA: chin, mid-lower lip, anterior floor of mouth IB: IA nodes, lower nasal cavity, hard and soft palate, lips and anterior tongue Common metastasis oral and anterior nasal cavity malignancies cancers of the mid face and submandibular gland
8	Levels II, III and IV: The Internal Jugular Nodes Levels II, III and IV are all part of the internal jugular or deep cervical chain The internal jugular chain is a common final pathway for the drainage from the parotid, preauricular, retropharyngeal, submandibular and submental groups The internal jugular nodes ultimately drain into the thoracic duct These nodes play an important role in surgical management, since extracapsular spread extending from these nodes to the jugular vein is an indication for radical neck dissection
9	Level II Nodes: Superior Jugular Nodes Borders Superior: skull base at the margin of the jugular fossa Inferior: lower body of the hyoid bone, Anterior: Posterior edge of the submandibular gland Posterior: Posterior edge of the sternocleidomastoid 2A: Anterior, lateral or medial to the internal jugular vein OR posterior to the vein but inseparable from it 2B: Posterior to the internal jugular vein but separated from it by a fat plane Drainage: Drainage from the following nodal groups: facial, parotid, IA and IB nodes, retropharyngeal nodes Drainage from the following structures: nasal cavity, pharynx, larynx, middle ear Common metastasis: Supraglottic cancers (Nasopharynx, oropharynx, parotid, superglottic larynx, salivary glands)
10	Level II Node: The Jugulodigastric Node Location: immediately posterior to the submandibular gland Provides lymphatic drainage from the tonsils, oral cavity, pharynx and submandibular nodes
11	Level III Nodes: Middle Jugular Nodes Borders Superior: Hyoid bone Inferior: Lower margin of the cricoid cartilage Anterior: Common carotid/internal carotid artery Posterior: Posterior edge of the sternocleidomastoid Drainage: Drainage from the following nodal groups: II, V Drainage from the following structures: base of tongue, tonsils, hypopharynx and larynx, Common metastasis Oral cavity, nasopharynx, oropharynx, hypopharynx and larynx
12	Level IV Nodes: Lower Jugular Nodes Borders Superior: Lower margin of the cricoid arch Inferior: Clavicle Anterior: Common carotid artery Posterior: Posterior edge of the sternocleidomastoid Drainage: From the following nodal groups: II, III, V, retropharyngeal, pretracheal (VI), recurrent laryngeal From the following structures: hypopharynx, larynx, thyroid Common metastasis: Supraglottic larynx, hypopharynx, esophagus, thyroid
13	Posterior Triangle: Level V Nodes Borders Superior: Skull base Inferior: Clavicle Anterior: Posterior to the sternocleidomastoid, anterior-scalene Posterior: Anterior edge of the trapezius muscle 5A: Above the level of the cricoid arch 5B: Below the level of the cricoid arch Drainage: Level V nodes freely communicate with the internal jugular chain (II, III and IV) From the following nodal groups: occipital, postauricular/mastoid From the following structures: scalp, posterior neck and shoulders, tonsils, base of tongue Common metastasis: Nasopharynx and oropharynx (generally less often involved), cervical esophagus
14	In the Midline: Level VI Nodes Also known as the visceral nodes, contains pretracheal and paratracheal nodes and perithyroid nodes Borders: Superior: Lower body of the hyoid bone Inferior: Superior edge of the manubrium Lateral: Common/internal carotid arteries Drainage: From the following structures: thyroid, larynx, hypopharynx, cervical esophagus Common Malignancies: Thyroid, lung, cervical esophagus and larynx
15	Level VI Node: The Delphian Node Definition: The Delphian node is a solitary node which lies immediately superfical to the cricoid membrane Significance: frequently enlarged in thyroid and subglottic laryngeal pathologies
16	Behind the Sternum: Level VII Nodes Borders: Superior/anterior: Manubrium Lateral: Left and right common carotid arteries Inferiorly: Innominate vein Drainage: Thyroid, larynx, thorax Common malignancies: Thyroid, larynx, lung, breast
17	Anatomic Nodes Nodes not included in the numeric classification are named anatomically Parotid Mastoid/Retroauricular Occipital Supraclavicular Retropharyngeal
18	Parotid Nodes Location: within the substance of and adjacent to the parotid gland Drainage: lateral and frontal scalp, anterior auricle and external auditory canal, buccal mucosa Drain predominantly into the internal jugular chain (level II nodes) Pathology: infections of the mastoid, scalp and parotid, parotid and facial malignancies
19	Mastoid Nodes Also call the posterior auricular nodes Location: over the SCM at its insertion onto the mastoid tip Drainage: posterior auricular region (hence, the name) Drain predominantly into the parotid nodes, internal jugular and spinal accessory nodes
20	Occipital Nodes Location: Superficial group: Between the SCM and trapezius, superficial to the splenius and deep to superficial fascia Deep group: Deep to splenius muscle, along the course of the occipital artery Drainage: Superficial: Occipital scalp and posterior cervical skin Deep: Deep musculature of the neck in the occipital region
21	Supraclavicular Nodes Location: nodes which are at or below the level of a portion of the clavicle as seen on axial imaging Drainage: thorax, mediastinum, abdomen via the thoracic duct Frequently involved in metastatic disease (breast, lung, etc)
22	Retropharyngeal Nodes Location: between the pharyngeal wall and the prevertebral fascia Lateral group: Just medial to the internal carotid artery Medial: more midline and inferior These are often clinically silent nodes, since they cannot be detected by palpation Drainage: nasal cavity, sphenoid and ethmoid sinuses, hard and soft palate, nasopharynx and posterior wall of the cricoid Drain into the Level II nodes Pathology: Infection (children), oropharyngeal and nasopharyngeal cancers Enlarged lateral nodes may be an early sign of nasopharyngeal cancer
23	CT Appearance of Abnormal Nodes Abnormal nodes are defined by the following characteristics: Size/Shape Extranodal Spread/Obliteration of normal tissue planes Nodal necrosis Abnormal enhancement
24	Appearance of Abnormal Nodes Size Level I, II and III: Abnormal size is >1.5 cm All other nodes: Abnormal size is >1 cm OR multiple nodes 0.6 - 1.5 cm in an expected nodal draining area Size is neither a sensitive nor specific discriminator Shape “lima bean shape” is generally regarded as more likely to be a hyperplastic node and therefore benign Metastasis are more likely to be spherical
25	Appearance of Abnormal Nodes: Abnormal Size and Shape in Lymphoma Multiple enlarged nodes and lymphoid tissue hypertrophy in a patient with lymphoma
26	Appearance of Abnormal Nodes: Abnormal Size and Shape in Lymphoma Calcified node in a patient with treated lymphoma
27	Appearance of Abnormal Nodes: Abnormal Size and Shape in Metastatic Disease Round nodes in a pt with metastatic head and neck cancer
28	Appearance of Abnormal Nodes: Extracapsular Spread Extracapsular extension in two patients with head and neck cancer
29	Abnormal Nodes: Obliteration of Normal Tissue Planes Multiple enlarged nodes obliterating normal tissue planes in a patient with Hodgkin’s Lymphoma with an associated necrotic tissue mass
30	Appearance of Abnormal Nodes: Central Necrosis Central Necrosis Highly specific for metastatic disease Characterized by low attenuation in the central part of the node The periphery of node is usually thick and enhancing Ddx: Suppurative or abscessed node (e.g. tuberculosis), central fatty hilum
31	Appearance of Abnormal Nodes: Central Necrosis Suppurative node in a pt with Tuberculosis scrofula generally presents as a painless neck mass May calcify following treatment Displays thick rim enhancement
32	Appearance of Abnormal Nodes: Central Necrosis Head and neck cancer pt with recurrent disease eroding the mandible
33	Appearance of Abnormal Nodes: Abnormal Enhancement
34	Cervical node staging and clinical management Staging of Nodal Metastatsis NX: Regional lymph nodes cannot be assessed N0: No regional nodal metastasis N1: Metastasis in a single ipsilateral lymph node, <3 cm in greatest dimension N2a: Metastasis in a single ipsilateral lymph node, 3-6 cm in greatest dimension N2b: Metastasis in multiple ipsilateral lymph nodes, none >6 cm N2c: Metastasis in bilateral or contralateral nodes, none >6 cm N3: Metastasis in a lymph node >6 cm Staging based on imaging directs clinical management of head and neck cancer patients
35	Surgical Approach Surgical approach to the head and neck cancer patient is based on extent of nodal disease Surgical options include Radical neck dissection Modified radical neck dissection Selective neck dissection Supraomohyoid neck dissection Lateral neck dissection Anterior compartment neck dissection Posterolateral neck dissection
36	Radical Neck Dissection En bloc clearance of all fibrofatty tissue from one side of the neck, including level I-V nodes, nodes surrounding the tail of the parotid, spinal accessory nerve, internal jugular vein and SCM Prior to advances in imaging and classification, this technique was widely used for neck disease of any stage Now, radical neck dissection is limited to patients with advanced neck disease, recurrent disease after chemoradiation or gross extracapsular spread to the spinal accessory nerve, SCM and internal jugular vein
37	Modified Radical Neck Dissection Like the modified radical neck dissection, there is removal of level I-V nodes and some parotid nodes but involves the preservation of one or more of the following three structures: the spinal accessory nerve, the internal jugular vein or SCM Modified radical neck dissection is indicated for any clinically palpable neck disease but without extracapsular spread to involve those structures
38	Selective Neck Dissection Refers to neck dissection in which one or more lymph node groups usually removed in a radical neck dissection are preserved Supraomohyoid neck dissection: removal of level I, II and III nodes Preferred for N0 and N1 disease that originate from the oral cavity Lateral neck dissection: removal of level II, III and IV nodes Preferred in treatment of cancers of the oropharynx, hypopharynx or larynx Anterior compartment neck dissection: removal of level VI nodes Preferred in treatment of cancers of the thyroid, hypopharynx, cervical trachea, cervical esophagus, and subglottic larynx Posterolateral neck dissection: removal of level II, III, IV and V nodes and postauricular and suboccipial nodes Preferred treatment of cutaneous malignancies of the scalp, postauricular and suboccipital regions
39	Summary Nodal classification has evolved based on surgical and image based anatomic landmarks. The presence and extent of abnormal nodes will alter the surgical and clinical management of head and neck cancer patients. Knowledge of cervical nodal anatomy and the appearance of abnormal nodes will allow the radiologist to better assist the clinician in diagnosis and management of these patients.
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