Midline Neck Mass in Adults: Diagnostic and Management Approach
For an adult presenting with a midline neck mass, you must immediately assess malignancy risk and obtain contrast-enhanced CT or MRI of the neck, followed by targeted physical examination including visualization of the upper aerodigestive tract, as midline masses carry a diverse differential including thyroglossal duct cyst, thyroid malignancy, or metastatic spread from laryngeal cancer (Delphian node). 1
Initial Risk Stratification
Identify high-risk features that mandate immediate workup:
- Duration criteria: Mass present ≥2 weeks without significant fluctuation or of uncertain duration, with no infectious etiology 1
- Physical examination red flags:
Midline-Specific Differential Diagnosis
The location matters critically. Midline neck masses warrant special consideration given their unique differential diagnosis 1:
- Thyroglossal duct cyst (most common benign midline lesion) 1
- Thyroglossal duct carcinoma 1
- Thyroid malignancy 1
- Metastatic laryngeal cancer (Delphian node) 1
- Bilateral cervical metastases from nasopharyngeal, tongue base, or midline oral cavity cancers 1
Mandatory Imaging
Order contrast-enhanced CT neck (or MRI) immediately for any patient deemed at increased risk for malignancy. 1 This is a strong recommendation based on the need to:
- Localize and characterize the mass 1
- Assess for additional nonpalpable masses 1
- Screen the upper aerodigestive tract for primary malignancy 1
- Define extent of disease for staging 1
CT versus MRI choice: Either modality is acceptable, though MRI may be preferable if radiation exposure is a concern 1. The clinician chooses based on the specific clinical situation 1.
Targeted Physical Examination
Perform or refer for visualization of the larynx, base of tongue, and pharynx using flexible laryngoscopy. 1 This is mandatory because:
- Midline oral cavity and tongue base cancers can metastasize bilaterally 1
- Laryngeal primaries commonly spread to midline nodes 1
- Physical examination alone is insufficient—endoscopic examination is essential 1
Palpation technique must include:
- Bimanual floor of mouth examination 1
- Tongue base palpation (lateral and posterior views) 1
- Assessment of all lymph node levels 1
Tissue Diagnosis Strategy
Use fine-needle aspiration (FNA) instead of open biopsy, or refer to someone who can perform FNA. 1 Open biopsy should be avoided as it:
Critical Pitfalls to Avoid
Do not assume a midline mass is benign based on clinical impression alone. Even lesions that appear consistent with thyroglossal duct cyst can harbor malignancy, including mixed papillary-follicular thyroid carcinoma 2. The clinical and radiological appearance may be deceptive 2.
Do not delay imaging. Imaging is not a substitute for physical examination, but it is an essential adjunct that must be obtained promptly 1.
Do not perform empiric antibiotic therapy without clear infectious etiology. This delays diagnosis of malignancy and is not supported by guidelines for masses without infectious history 1.
Patient Communication
Explain to the patient:
- The significance of being at increased risk for malignancy 1
- The rationale for recommended diagnostic tests 1
- Criteria that would trigger need for additional evaluation 1
Document a clear follow-up plan to assess resolution or final diagnosis 1.
Referral Threshold
Refer immediately to head and neck surgery or otolaryngology if the patient meets high-risk criteria, as experienced clinicians can distinguish midline neoplasms from metastatic disease and determine appropriate surgical approach 1. The guideline acknowledges that clinicians are not obliged to follow the standard paradigm if they are reasonably certain clinical findings are inconsistent with malignancy risk 1.