Thyroid nodule

Question 1

What types of nodules can appear on the thyroid?

Answer 1

Nodules may be cystic, colloid, hyperplastic, adenomatous or cancerous.

Goitre is enlargement of the thyroid gland but goitres can be multinodular or solitary

Question 2

What are the most common causes of thyroid nodules?

Answer 2

• Iodine deficiency (not UK) –> goitre
• Where iodine is added to salt –> AI conditions (Hashimoto’s thyroiditis and Graves’) are more common causes
• Medication (lithium and amiodarone) –> thyroid enlargement
• May also occur in pregnancy and menopause

Question 3

How common are thyroid lumps?

Answer 3

Present in 4-7% of adults

• 95% are benign
• Uncommon in children and adolescents but if present then more likely to be cancerous

Question 4

What are the risk factors for thyroid nodules?

Answer 4

• Low iodine consumption*
• Excessive iodine consumption (seaweed) –> goitres
• Malignancy
• Radiation exposure
• Smoking
• FH
• Medication e.g. amiodarone and lithium

Research shows that milk alternative drinks do not have enough iodine.

Question 5

How do thyroid lumps present? What are the red flags?

Answer 5

• Asymptomatic -noticed by family or in mirror
• Tracheal compression
• Thyroid moves with swallowing
• ?Asymmetry/enlargement
• ?Tenderness
• Regional lymphadenopathy

Red flags -

• stridor associated with thyroid mass
• child
• hoarseness or voice changes
• rapidly enlarging
• FH of thyroid cancer, radiation, pain

Question 6

Name some causes of thryoid lumps and swellings (10)

Answer 6

• Non-toxic (simple) goitre - non-functioning nodules with normal TFTs
• Toxic multinodular goitre - functioning with abnormal TFTs
• Retrosternal goitre (multinodular)
• Hyperplastic nodule (single or part of multinodular goitre)
• Colloid nodule
• Thyroid adenoma
• Thyroid cyst
• Thyroid carcinoma
• Graves’ - diffuse enlarged and overactive thyroid
• Hashimoto’s thryoiditis - AI destruction of the gland may cause diffuse enlargement
• De Quervain’s thyroiditis - neck pain, lethargy soon after URTI
• Active suppurative thyroiditis - from bacterial or fungal infection causing abscess

Question 7

Name some non-thyroid causes of lumps/swellings in the neck.

Answer 7

• Congenital/developmental:
  
  • Thyroglossal cyst
  • Brachial cyst
  • Pharyngeal pouch
  • Dermoid cyst
  • Laryngocele
• Lymph nodes
• Salivary gland swellings
• Non-thyroid benign and malignant tumours - lipoma, fibroma, vascular tumours, sarcomas

Question 8

What investigations would you do for thyroid nodules?

Answer 8

TFTs - if abnormal TFTs and no suspicious features then refer; thyroid swelling and normal TFTs are red flag and should also be referred. Refer where cancer is supected.

US - good for detection and characterising thyroid nodules. Helps inform aspiration and cytology.

FNA - under US guidance

Basal plasma calcitonin and carcinoembryonic antigen (CEA) - measure if thyroid medullary cancer is suspected

CT/MRI - may be required to study mediastinal spread and regional lymph node involvement

Question 9

Describe the thyroid nodule classification on ultrasound.

Answer 9

British Thyroid Association (BTA) U-Classification

Nodules are classified into categories U1 to U5, based on :

• echogenicity,
• contour,
• halo,
• colloid artefact,
• calcification and
• vascularity
• U1 = normal thyroid parenchyma,
• U2 = benign nodule,
• U3 = indeterminate/equivocal nodule,
• U4 = suspicious nodule
• U5 a= malignant nodule.

FNAC is recommended for nodules classified as U3 or above.

Question 10

Describe the thyroid nodule classification on cytopathology.

Answer 10

Bethesda system - categorises malignancy risk on FNAC

Question 11

How do malignant nodules appear on uptake scans?

Answer 11

Usually cold nodules