Thyroid cancer

Question 1

What is thyroid cancer?

Answer 1

This is the most common endocrinological malignancy and is more common in women than men.

Question 2

How does thyroid cancer present?

Answer 2

Most commonly presents as an asymptomatic thyroid nodule detected by palpation or ultrasound in a woman (30-40)

Question 3

Types of thyroid cancer

Answer 3

Papillary (80%):
Well-differentiated with a tendency towards multicentricity and lymph node involvement.
Follicular (10%):
Spreads through direct haematogenous invasion.
Widely invasive forms are aggressive.
Hurthle cell is a sub-type of a follicular cell.
Medullary (4%):
Originates in thyroid parafollicular C cells
The tendency to multicentricity and early lymph node spread.
Anaplastic (3%):
Undifferentiated neoplasm with mitosis and vascular invasion.
Local encroachment into recurrent laryngeal nerve and trachea, muscle and/or oesophagus.
Lymphoma (2%):
B-cell type non-Hodgkin’s lymphoma.
Arises in the setting of pre-existing Hashimoto’s thyroiditis.

Question 4

Signs and symptoms of thyroid cancer

Answer 4

This is an asymptomatic thyroid nodule. 
Hoarseness (uncommon) 
Dyspnoea (uncommon)
Dysphagia (uncommon) 
Tracheal deviation (uncommon)
Cervical lymphadenopathy (uncommon)

Question 5

Investigations of thyroid cancer

Answer 5

TSH-
Usually normal
Fine needle biopsy-
Cytology suggests histological features.
Done if TSH isn’t suppressed.
Ultrasound-
Definition of dimensions of nodules and solid/cystic components
Used to guide fine-needle biopsy
Suspicious features include micro-clacifications
Laryngoscopy-
Ipsilateral paralysed vocal cord
Consider doing:
FT4, FT3, I-123 thyroid scan
Core biopsy when fine-needle suggests lymphoma
CT neck to evaluate lymph nodes in people with medullary cancer
Serum calcitonin (high in medullary cancer)

Question 6

Differentials of thyroid cancer

Answer 6

Benign thyroid nodule

Question 7

Management of thyroid cancer

Answer 7

Thyroid cancer managed by an MDT. 
Papillary, follicular or Hurthle cell: 
Surgery followed by radioactive iodine ablation and suppression of TSH for most patients.
Medullary: 
Total thyroidectomy 
Anaplastic: 
Total thyroidectomy or combined chemoradiotherapy 
Lymphoma: 
Combined chemoradiotherapy