What is a pseudo‑goitre and how should it be evaluated and managed?

Pseudo-Goitre: Definition and Clinical Approach

A pseudo-goitre refers to apparent thyroid enlargement that is not actually due to true thyroid gland pathology, but rather mimics goiter on physical examination due to anatomical variants, adjacent neck masses, or positioning artifacts.

What Constitutes a Pseudo-Goitre

The term "pseudo-goitre" describes situations where the neck appears enlarged or a mass is palpable in the thyroid region, but imaging reveals the thyroid gland itself is normal. Common causes include:

• Anatomical variants: Short, thick neck with prominent fat pads or muscle
• Adjacent structures: Enlarged lymph nodes, parathyroid masses, thyroglossal duct cysts
• Vascular structures: Prominent carotid arteries or jugular veins
• Non-thyroidal masses: Lipomas, dermoid cysts, or other soft tissue masses in the anterior neck

Diagnostic Evaluation

The cornerstone of evaluation is thyroid ultrasound, which definitively distinguishes true thyroid pathology from pseudo-goitre 1.

Initial Assessment

1. Measure serum TSH - This is the most sensitive and reliable index of thyroid function and should be the first biochemical test 1, 2

2. Perform thyroid ultrasound - US is the preferred first-line imaging modality for any suspected goiter or neck mass 1. Key advantages:

   • Confirms whether the mass originates from thyroid tissue
   • Characterizes thyroid size and morphology
   • Identifies non-thyroidal structures
   • Evaluates for true nodules if thyroid pathology exists

When Additional Imaging is Needed

• CT neck without contrast is superior to US only when evaluating substernal extension or deep retropharyngeal involvement 1
• MRI is an alternative to CT but less preferred due to respiratory motion artifact 1
• Radionuclide scanning is NOT indicated for pseudo-goitre evaluation, as it does not help distinguish thyroid from non-thyroid masses in euthyroid patients 1

Management Strategy

Once ultrasound confirms the absence of true thyroid pathology (pseudo-goitre), no thyroid-specific treatment is required.

Clinical Algorithm

1. If US shows normal thyroid gland with mass arising from adjacent structures:

   • Characterize the actual source of the mass
   • Refer appropriately (e.g., lymph node biopsy if indicated, vascular surgery consultation for vascular anomalies)

2. If US shows normal thyroid with no discrete mass (anatomical variant):

   • Reassure the patient
   • No further thyroid evaluation needed
   • Document findings to avoid repeated unnecessary workup

3. If US reveals actual thyroid pathology (not pseudo-goitre):

   • Follow standard goiter management guidelines 2
   • FNA is indicated for nodules >10mm with intermediate US risk features, or >20mm for low-risk lesions 2

Critical Pitfalls to Avoid

• Do not proceed to FNA or surgery based solely on palpation without ultrasound confirmation of thyroid origin
• Do not initiate levothyroxine suppression therapy - this is not recommended even for true benign thyroid nodules 2, and certainly has no role in pseudo-goitre
• Do not order radioiodine scanning in euthyroid patients with suspected goiter, as it has low positive predictive value and will not distinguish pseudo-goitre from true goiter 1
• Avoid contrast-enhanced CT unless there is concern for infiltrative neoplasm, as non-contrast imaging is sufficient for goiter characterization 1

The key principle is that ultrasound rapidly and definitively resolves the diagnostic question, preventing unnecessary interventions and directing appropriate management based on the actual pathology present.