Thyroid cancer Flashcards
Where does the thyroid sit?
C5-T1
Describe the general structure of the thyroid
2 lobes connected by isthmus
How is the superior aspect of the thyroid perfused?
Superior thyroid artery
Is a branch off the external carotid artery
How is the inferior aspect of the thyroid perfused?
Inferior thyroid artery
Is a branch off thyrocervical trunk which is a branch off the subclavian artery
What is the histology of the thyroid
Outer follicular cells which trap iodine from the circulation,
Inner colloid which is where T3 and T4 is synthesised and produces thyroglobulin
What is thyroglobulin used for?
Involved with iodide storage and thyroid hormonogenesis
Iodine is trapped and diffuses into the colloid where it binds to… to form…
tyrosine residues, to form T1 or T2
Where are the tyrosine residues which the iodine bind onto found?
Tyrosine residues are on thyroglobulin
What catalyses the binding of iodine to tyrosine residues?
TPO enzyme (thyroid peroxidase)
What stimulate the release of T1 and T2?
TSH-receptor binding
The release of T1 and T2 leads to…
formation of T3 (T1+T2) and T4 (T2+T2) which are released into the general circulation
What is the most common type of thyroid carcinoma?
Papillary carcinoma
What types of thyroid cancer are there?
Papillary carcinoma
Follicular carcinoma
Anaplastic (many metastases)
Lymphoma
Medullary cell cancer
What are symptoms of thyroid cancer
Thyroid nodules, hard and irregular.
May have compression locally causing a hoarse voice (recurrent laryngeal nerve)
How do you diagnose a thyroid carcinoma?
Fine needle aspiration biopsy
Thyroid function tests
Ultrasound thyroid
