Which head and neck lesions drain into which levels of lymph nodes?

Head and Neck Lymphatic Drainage Patterns by Primary Site

The location of a neck mass predicts the primary tumor site based on established lymphatic drainage patterns: lip and oral cavity lesions drain to levels I-III, oropharyngeal/hypopharyngeal/laryngeal primaries drain to levels II-IV, and nasopharyngeal/thyroid primaries drain to level V, though individual lymphatic mapping can reveal unexpected drainage patterns requiring comprehensive evaluation. 1

Primary Site-Specific Drainage Patterns

Oral Cavity (Lip, Tongue, Floor of Mouth, Alveolar Ridge)

• Typical drainage: Levels I, II, and III 1
• Midline or anterior tongue lesions: Require bilateral submandibular dissection and contralateral nodal assessment due to bilateral drainage risk 1
• Submandibular gland involvement: Only occurs with ipsilateral oral cavity tumors through direct extension or from involved level I nodes, never from hematogenous metastasis 2
• Level IB considerations: Include ipsilateral level IB if the level is positive, if structures drain to IB as first echelon (oral cavity, anterior nasal cavity), with submandibular gland involvement, or with ipsilateral level IIA nodes showing extracapsular extension 1

Oropharynx (Base of Tongue, Tonsil, Soft Palate)

• Typical drainage: Levels II, III, and IV 1
• Bilateral drainage risk: Base of tongue and palate tumors frequently drain bilaterally, requiring bilateral neck dissection for midline or near-midline lesions 1, 3
• Retropharyngeal nodes: Commonly involved and should be included in radiation treatment volumes 1

Hypopharynx and Larynx

• Typical drainage: Levels II, III, and IV 1
• Infraglottic laryngeal cancers: Require level VI (central compartment) dissection in addition to lateral neck levels II-IV 3
• Supraglottic larynx: Has bilateral drainage patterns requiring bilateral neck assessment 1

Nasopharynx

• Typical drainage: Level V and retropharyngeal nodes 1
• Bilateral drainage: Common due to midline location 1
• Retropharyngeal nodes: Routinely involved and must be included in treatment planning 1

Thyroid

• Typical drainage: Level V, with level VI (central compartment) as primary drainage 1

Cutaneous Malignancies (Melanoma, Squamous Cell Carcinoma)

General Patterns

• Can drain to any level: I through V, plus nontraditional sites including parotid, external jugular, perifacial, suboccipital, and postauricular regions 1, 4
• Level IIB involvement: Occurs in 15.9% of all cutaneous head and neck cases, most commonly from scalp and ear primaries 4

Site-Specific Cutaneous Drainage

• Scalp lesions: Drain to suboccipital and postauricular nodes (unique to scalp), with frequent level IIB involvement 4, 5
• Periocular and cheek lesions: External jugular nodes involved in over 25% of cases 4
• Nose and lip lesions: Frequently drain to perifacial nodes 4
• Multiple basin drainage: Occurs in 25% of head and neck melanomas, requiring comprehensive lymphoscintigraphy mapping 6

Critical Anatomic Considerations

Level IV and Supraclavicular Fossa

• 50% of masses arise from primaries below the clavicle (chest, gastrointestinal tract, breast) rather than head and neck sites 1
• Requires thorough evaluation for distant primary when nodes present in these locations 1

Aberrant and Unexpected Drainage

• Lymphoscintigraphy reveals discordant drainage in 43% of cases compared to clinically predicted patterns 1, 5
• Unexpected drainage to level IV or contralateral nodes can occur even from well-lateralized tumors 1
• Sentinel nodes appear within 1-3 hours of radiotracer injection, with some visible in the first minute 1

Clinical Pitfalls to Avoid

Failed Lymphatic Mapping

• Floor of mouth tumors: Sentinel nodes may not visualize due to close proximity to injection site (shine-through effect) 1
• Metastatic blockage: Can prevent sentinel node visualization, requiring proceeding directly to neck dissection 1

Inadequate Nodal Coverage

• Never omit level VI for infraglottic laryngeal cancers 3
• Never perform unilateral dissection for midline tumors without bilateral assessment 3
• Include at least one level below the involved node levels in selective neck dissection 1

Nontraditional Sites

• External jugular nodes: Present in over 15% of all cutaneous cases, frequently missed without lymphoscintigraphy 4
• In-transit nodes: Can occur between primary tumor and regional basin, requiring identification on preoperative imaging 1