11/14/24, 10\:40 AM Thyroid Cancer and Thyroid Nodules

Thyroid Cancer and Thyroid Nodules

Table of contents
Key points ⚡
Succinct notes to superpower your revision
Thyroid cancer\: malignancy of the thyroid gland, with 3,900 new cases annually in the UK.
Thyroid nodules\:
Types\:
Papillary\: 90%, spreads via lymphatics, associated with radiation exposure.
Follicular\: spreads haematogenously, presents with thyroid swelling.
Medullary\: cancer of calcitonin cells, associated with MEN 2A.
Anaplastic\: aggressive, poor prognosis, metastases at presentation.
Lymphoma\: associated with Hashimoto’s thyroiditis.
Risk factors\: female sex, obesity, benign thyroid disease, radiation exposure, family history, SLE.
Symptoms\: neck lump, hoarse voice, dysphagia, odynophagia, dyspnoea, stridor, weight loss, fatigue, diarrhoea, bone pain,
pulsatile lesion.
Examination\: assess for neck lump, thyroid goitre, stridor, hoarseness, cachexia.
Investigations\:
Bedside\: ECG (arrhythmias), urinalysis (urinary catecholamines).
Laboratory\: thyroid function tests, thyroid autoantibodies, plasma calcitonin, CEA.
Imaging\: ultrasound, MRI/CT for metastasis.
FNAC\: Thy classi
Staging\: TNM classi
Management\:
Referral\: 2-week wait referral for unexplained thyroid lumps with red
Surgery\: primary treatment, possibly followed by radioactive remnant ablation.
Adjuvant therapy\: chemoradiotherapy or immunotherapy for advanced cases.
Thyroxine replacement\: lifelong after total thyroidectomy.
Complications\:
Cancer-related\: shortness of breath, hoarseness, airway obstruction, dysphagia, metastasis, death.
Surgery-related\: bleeding, infection, recurrent laryngeal nerve damage, need for lifelong thyroid hormone replacement
and monitoring, need for further procedures.
Article 🔍
A comprehensive topic overview

Introduction

Thyroid cancer is a malignancy of the thyroid gland. There are 3,900 new thyroid cancer cases diagnosed annually in the
UK, making it the 20 th 1
most common cancer in the UK.
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Thyroid nodules and goitre are common; many are picked up incidentally on imaging, and most are benign. A nodule is a
term used to de
swelling in the neck due to the enlargement of the thyroid gland.
This article will cover the classi
OSCE guide to performing a neck lump examination.

Aetiology

Anatomy

The thyroid gland is an endocrine gland situated in the anterior midline of the neck, just anteroinferior to the larynx. It
consists of a right and a left lobe, connected by a central isthmus. The isthmus overlies the second to fourth tracheal rings.
It is surrounded by the pre-tracheal fascia in the neck.
2
The thyroid gland receives arterial supply from the superior and inferior thyroid arteries, branches of the external carotid
artery and the thyrocervical trunk of the subclavian artery, respectively. Occasionally some individuals will have a thyroid
ima artery, arising from the brachiocephalic trunk.
Venous drainage of the thyroid gland is via the superior, middle and inferior thyroid veins. The superior and middle veins
drain into the internal jugular vein, while the inferior thyroid vein drains into the brachiocephalic vein.
3
Figure 1. Anterior view of the thyroid
gland.
The thyroid gland receives sympathetic innervation from the sympathetic chain. The sympathetic innervation has
vasomotor control of the thyroid gland, but the pituitary gland regulates the secretory function. Lymphatic drainage is to
3
the paratracheal and deep cervical lymph nodes .
The thyroid gland is an endocrine organ comprising follicular cells and parafollicular cells. Follicular cells produce thyroid
hormone (T3/T4) and surround a central colloid. Parafollicular cells are involved in the production of calcitonin, which
works to reduce serum calcium.

Classi

Thyroid cancers are characterised according to their morphology.
The most common subtype is papillary thyroid cancer (accounting for 90%). This characteristically spreads via lymphatics
and can commonly present as a neck node. It is associated with radiation exposure.
4
The second most common is follicular carcinoma. This is more likely to present with thyroid swelling and has a
haematogenous route of spread.
Medullary thyroid carcinoma is a cancer of the calcitonin cells associated with multiple endocrine neoplasia type 2A
(MEN 2A). These patients are more likely to have a family history and may also have other features of MEN 2A (e.g.
hypertension secondary to a phaeochromocytoma).
4
Anaplastic thyroid carcinoma is an undi
metastases at presentation. It has a poor prognosis, and survival following diagnosis is usually limited to several months
only.
Lymphoma is another cancer subtype that can occur in the thyroid gland. This is associated with Hashimoto’s thyroiditis, an
in
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Risk factors

Risk factors for thyroid cancer include\:
1
Female sex (the reason for this is unclear)
Obesity
Benign thyroid disease (Hashimoto's, thyroid adenomas, a goitre)
Radiation exposure (thyroid gland is sensitive to radiation)
Family history (certain genetic disorders such as multiple endocrine neoplasia)
Systemic lupus erythematosus (SLE)

Clinical features

History

Typical symptoms of thyroid cancer include\:
Neck lump
Hoarse voice
Dysphagia
Odynophagia
Dyspnoea
Stridor
General symptoms may include\:
Weight loss, anorexia
Lethargy, fatigue
Diarrhoea
Bone pain (metastatic disease)
Pulsatile lesion (metastatic disease)

Clinical examination

All patients with a goitre or neck lump require a full neck examination. If there is concern that the lump arises from the
thyroid, a thyroid status examination should be performed.
Typical clinical
General cachexia
Neck lump
Thyroid goitre
Stridor or hoarseness
Assessing thyroid nodules
When assessing a thyroid nodule, features that increase suspicion of malignancy include\:
Age \<20 years or >60 years
Firmness of nodule
Rapid growth
Fixed to adjacent structures
Vocal cord paralysis
Regional lymphadenopathy
History of neck irradiation
Family history of thyroid cancer
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Di

Thyroid cancer typically presents as a thyroid lump, hoarseness/voice changes, shortness of breath and/or systemic
features (weight loss, anorexia).
These symptoms have a wide range of potential causes which must be considered.

Neck lump

Other possible causes of a neck lump include\:
Benign thyroid disease
Thyroglossal cyst
Lymphadenopathy secondary to another cancer (e.g. Virchow’s node & gastric cancer) or infection

Hoarseness

Other possible causes of hoarseness include\:
Laryngitis
Laryngeal cancer
Post-operative complication (e.g. following neck surgery)

Shortness of breath

Other possible causes of shortness of breath include\:
Chest infection
Exacerbation of asthma or COPD
Pleural e
Pulmonary embolism
Cardiac causes (e.g. myocardial infarction)

Investigations

Bedside investigations

Relevant bedside investigations include\:
ECG\: endocrine disorders of the thyroid gland can cause arrhythmias (e.g. hyperthyroidism and atrial )
Urinalysis\: the presence of urinary catecholamines may indicate a phaeochromocytoma or paraganglioma, which may
indicate a diagnosis of MEN

Laboratory investigations

Relevant laboratory investigations include\:
Thyroid function tests\: thyroid cancer is usually associated with a euthyroid state; however, advanced cancers can
cause hypothyroidism (due to the destruction of healthy thyroid tissue) or hyperthyroidism (due to the presence of more
active cells)
Thyroid autoantibodies
Plasma calcitonin and carcinoembryonic antigen (CEA)\: if suspicious for MEN
Genetic testing may be indicated in the presence of a strong family history or with a diagnosis of medullary thyroid cancer
(due to its association with MEN)

Imaging

Relevant imaging investigations include\:
Ultrasound\: all patients with a thyroid lump require an ultrasound scan. Radiological features of the lump are utilised, as
part of the British Thyroid Association ‘U’ classi, to determine the risk of malignancy and whether
aspiration (FNA) is required.
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Cross-sectional imaging (MRI/CT)\: performed for retrosternal disease or if suspicious of metastatic disease

Fine needle aspiration cytology (FNAC)

Fine needle aspiration involves aspirating a thyroid tissue sample under ultrasound guidance. FNA cytology results are
graded using the Thy classi.
5
Table 1. Fine needle aspiration cytology score (Thy classi
FNAC
Interpretation Management
score
Thy1 Non-diagnostic Repeat FNAC
Thy2 Benign
Reassuring if this aligns with the ultrasound

Thy3 Equivocal
Repeat FNAC or diagnostic
hemithyroidectomy (removing half the
thyroid gland containing the nodule to reach
a tissue diagnosis)
Thy4
Suspicious for
malignancy
Diagnostic hemithyroidectomy
Thy5 Malignant
Managed according to tumour type and
MDT outcome

Additional investigations

Additional relevant investigations may include\:
Flow-volume loop studies\: for assessment of upper airway obstruction

Diagnosis

The diagnosis of thyroid cancer is made with the above investigations. The outcome of imaging and FNAC guides the
management of thyroid cancer.

Staging

Thyroid cancer staging is used during MDT discussion to prognosticate and decide on appropriate management. This is
calculated with
classi
1
TMN Classi
Tx Tumour cannot be assessed
T0 No tumour
T1a
T1b
Inside the thyroid gland, \<1cm
Inside the thyroid gland, 1-2cm
T
T2 Inside thyroid, 2-4cm
T3a
T3b
Inside thyroid, >4cm
Extra-thyroid spread to strap muscles, any size
T4a
T4b
Soft tissue invasion – trachea, larynx, oesophagus
Neck vessel invasion or spinal invasion
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N
M
Nx No information about lymph node spread.
N0 No lymph node spread
N1a
N1b
Spread to pretracheal, paratracheal, prelaryngeal
lymph or superior mediastinal nodes
Spread to cervical or retropharyngeal nodes
M0 No distant metastatic spread
M1 Distant metastatic spread present

Management

Referral

If a patient presents with a suspected thyroid lump or goitre and acute airway compromise, they should be reviewed
urgently in the emergency department.
NICE advises considering a 2-week wait (urgent suspected cancer) referral for all patients with an unexplained thyroid
lump, especially if they have red
Unexplained hoarseness or voice changes
Associated lymphadenopathy
Sudden onset of an expanding painless thyroid mass
Any other red
Compressive symptoms of dysphagia, or breathlessness

Surgical management

The primary treatment modality for thyroid cancer is surgery. There is a role for adjuvant therapy in certain cases.
A diagnostic hemithyroidectomy is performed when the FNAC is suspicious but not diagnostic. Once the diagnosis of
malignancy is con
Figure 2. Intraoperative picture of thyroid
cancer, showing the macroscopic
appearance of the cancer.
Patients with di
destroys residual cells in the thyroid bed that may still be present. The use of this in medullary or anaplastic thyroid cancer
is less proven.
Anaplastic thyroid cancer is generally at an advanced stage at diagnosis, and this limits treatment options. Patients may
be o
Patients who have undergone total thyroidectomy will require life-long thyroxine replacement. If the parathyroids have
been removed, patients may also require calcium replacement.
Serum thyroglobulin is a marker used to monitor for signs of disease recurrence. This protein is only produced by
follicular cells. When raised, it is suspicious for disease recurrence and should prompt further investigation.
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Complications

Complications related to cancer

Complications of thyroid cancer can include\:
Shortness of breath
Hoarseness
Upper airway obstruction
Dysphagia
Odynophagia
Metastasis
Death

Complications of surgical management

Complications related to surgical management of thyroid cancer include\:
Bleeding\: expanding neck haematoma is a surgical emergency
Infection
Recurrent laryngeal nerve damage\: hoarseness or stridor if bilaterally
The need for lifelong thyroid hormone replacement and monitoring of thyroid function tests
The need for calcium/vitamin D replacement
The need for further procedures\: completion thyroidectomy, adjuvant RAA

References

Cancer Research UK. July 2023. Available from\: [LINK]
StatPearls. Anatomy, Head and Neck. July 2022. Available from\: [LINK]
Surgeon’s Approach to the Thyroid Gland\: Surgical Anatomy and the Importance of Technique. R Bliss et al. World J of Surg.
2000.
Katoh, H., Yamashita, K., Enomoto, T., & Watanabe, M. (2015). Classi
C l i n P a t h o l , 3 (1), 1045.
Guidance on the reporting of thyroid cytology specimens. Royal College of Pathologists. 2016. Available from\: [LINK]

Image references

Figure 1. CFCF. D i a g r a m m a t i c v i e w o f t h y r o i d g l a n d . License\: [CC BY-SA]
Figure 2. Marco BiCC BY-SA]

Reviewer

Miss Sarah Ellis
ENT ST3

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Test yourself

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