Thyroid Lumps

Red flags

  • Solitary thyroid lumps (nodules) may occasionally represent a primary thyroid malignancy.
  • Very large thyroid lumps may lead to tracheal compression and airway symptoms.
  • Quickly-expanding (over weeks), firm neck swelling may rarely be due to thyroid lymphoma or anaplastic carcinoma.
  • Generally, non-thyroid neck lumps eg sebaceous or branchial cysts become infected. Be wary of infected neck lumps, especially with systemic symptoms – err on the side of seeing and discussing these patients with a senior. 

 

Why is this important?

 Lumps in the thyroid are a common reason for referral to a head-and-neck clinic.  A significant majority are benign (90-95%), but all are assessed thoroughly to rule out malignancy.

 

When to involve the ENT registrar

  • Immediately: Discuss infected neck lumps and any neck lump that may be objectively (ie noisy breathing) compressing the airway.
  • Next working day: New thyroid masses should be referred to and assessed in a multidisciplinary head-and-neck outpatient clinic.

 

Clinical features 

Patients may present having become aware of a lump in the neck – thyroid lumps will be felt quite low down in the anterior neck, and will rise on swallowing.  Some patients will be referred from an endocrinology team, and other lumps may have been detected incidentally on imaging.

Less commonly, a large lump may cause cough, shortness of breath or stridor due to compression of the underlying trachea.  In some cases of malignancy, direct involvement of the recurrent laryngeal nerve may cause hoarseness.

Thyroid lumps can be solitary or multiple.  They may be associated with hyperthyroidism (eg a single “toxic” nodule) or hypothyroidism (especially in multinodular goitre), but a majority of patients will be euthyroid.

 

Differential diagnosis

Most thyroid nodules are adenomas.  These are benign, and are extremely common, especially with advancing age.

Malignant thyroid tumours are mostly carcinomas, most of which fall into four categories:

  • Papillary carcinoma (65%): the most common thyroid malignancy.  Has a good prognosis if diagnosed early, especially in young females.
  • Follicular carcinoma (30%): also associated with a good prognosis. Cannot be differentiated from follicular adenoma with fine-needle aspirate alone so a biopsy is required.
  • Medullary carcinoma (3%): less common, may be associated with MEN-2 syndrome.
  • Anaplastic carcinoma (1%): rare and highly aggressive.  Most tumours are unresectable and have a very poor prognosis.

Other rarer thyroid malignancies include lymphoma, squamous cell carcinoma and sarcoma.

Like other head-and-neck cancers, thyroid malignancies are staged using the TNM system.

 

Investigation 

Thyroid nodules over 1 cm in size are generally felt to warrant further investigation.  Initially nodules are assessed with ultrasound and fine-needle aspiration cytology (FNAC). FNAC can be performed in clinic, or may be performed at the time of ultrasound scan by the radiologist. Further imaging is only occasionally required.

Both the ultrasound scan and the results of FNAC give information about the probability of a nodule being malignant.  These results must be interpreted together, and in the light of the patient’s history and examination findings.

Cytology results are graded according to the Thy system:

  • Thy 1: insufficient sample.
  • Thy 2: likely to be benign.
  • Thy 3: possible malignancy.
  • Thy 4: likely to be malignant.
  • Thy 5: obviously malignant.

All patients should have their vocal cord movements assessed by flexible nasendoscopy prior to surgery.

 

Management 

The management of a thyroid lump may be conservative, medical or surgical.  Policies vary slightly between departments, and there are no hard-and-fast rules, but in general:

  • Thy 1: repeat FNAC.
  • Thy 2: conservative management with repeat USS+FNAC in around 6 months. Surgery may however be indicated for pressure symptoms, cosmesis, or other factors raising possibility of malignancy such as rapid enlargement, family history, suspicious ultrasound findings or patient concern.
  • Thy 3: usually hemithyroidectomy is performed for histological diagnosis.  If a malignancy is confirmed, a completion thyroidectomy followed by radio-iodine therapy is performed in most cases (except for some very small tumours with low-grade histology).
  • Thy 4: hemithyroidectomy may be performed, although many surgeons will perform total thyroidectomy.
  • Thy 5: total thyroidectomy followed by radioiodine therapy.

Thyroidectomy may be carried out with associated lymph node clearance (neck dissection). Other treatments include radiotherapy, chemotherapy (eg for thyroid lymphoma) or palliative care. All management decisions are made through a thyroid multidisciplinary team (MDT), and must take account of the patient’s comorbidities and wishes.  

 

 

Page last reviewed: 4 March 2017