Solitary Thyroid Nodule Flashcards
What percentage of thyroid nodules are malignant?
5% (1/20)
What percentage of women get a thyroid nodule?
5% (1/20)
What is differentiated thyroid cancer (DTC)?
Cancer of thyroid epithelium which is divided into:
Papillary thyroid carcinoma
Follicular thyroid carcinoma
What are the 5 types of malignant thyroid cancer?
Papillary thyroid carcinoma
Follicular thyroid carcinoma
Medullary thyroid carcinoma
Lymphoma
Anaplastic
What thyroid cancer spreads
- through lymphatics?
- through blood?
- Papillary
2. Follicular
What do medullary thyroid carcinoma secrete?
Calcitonin
What genetic syndrome are medullary thyroid carcinoma associated with?
MEN2
What do differentiated thyroid carcinoma (DTC) do?
Take up iodine and secrete thyroglobulin which can be used as a tumour marker
What is anaplastic thyroid carcinoma?
Rare, poorly differentiated but highly aggressive thyroid carcinoma
What presentation would make you consider a thyroid lymphoma?
Rapid onset mass in a 70-80 year old female with previous Hashimoto’s thyroiitis
What neck mass
- moves on swallowing?
- moves on tongue protusion?
- Thyroid mass
2. Thyroglossal cyst
What investigations would you do in a patient with a thyroid mass?
TFTs (if showing primary hyperthyroidism, request iodine uptake scan)
Ultrasound guided fine needle aspiration (USS-FNA)
What does an ultrasound guided fine needle aspiration (USS-FNA) test show?
US provides picture of the nodule itself
FNA gives cytology of the nodule
Together, these build up a picture of malignancy risl
What are the FNA result classifications and what do they correlate to?
Thy1 - just blood, inadequate information. repeat
Thy2 - benign
Thy3 - atypical
Thy4 - probably malignant
Thy5 - malignant
What are the US result classifications and what do they correlate to?
U2 - not worrying (may not even do FNA)
U3 - more worrying (33% malignant)
U4/U5 - very malignant
What are the limitations of FNA? How is this overcome?
Doesn’t show if capsular invasion (important for follicular carcinoma classification and essential for lymphoma diagnosis)
Core biopsy
What thyroid carcinoma can be diagnosed with USS-FNA and how?
Medullary
Presence of calcitonin/amyloid
What are 1. papillary and 2. follicular thyroid carcinoma differentiated into?
Papillary
- low risk (<50, <4cm)
- high risk (>50, >4cm)
Medullary
- minimally invasive (capsular invasion only)
- widely invasive (invasion of extrathyroid tissue or metastasis)
How are low and high risk papillary thyroid carcinoma treated?
Low risk - lobectomy
High risk- thyroidectomy
How are minimally and widely invasive follicular carcinoma treated?
Minimally invasive - Lobectomy
Widely invasive - thyroidectomy
How is thyroid lymphoma managed?
Chemotherapy
Steroids if acutely unwell
What is the biggest killer after treatment for thyroid cancer?
Hypocalcaemia
What follow-up scan is done 3-6 months after treatment and what does it involve?
Whole Body Iodine Scan
Radioactive iodine tablet (I-131)/rhTSH injection adminstered to patient
A few days later they return for a scan
Any remaning cancerous tissue would take up the iodine and show on the scan
Is rhTSH injection or I-131 tablet preferred in whole body iodine scan preparation?
Why?
rhTSH is preferred as it isn’t TSH dependent as doesn’t require the patient to be in the hypothyroid state
If a whole body iodine scan came back positive, what would be done?
Thyroid remnant ablation
Destruction of thyroid tissue with high dose radioactive iodine which destroys remaining cancerous tissue.
What are some disadvantages of thyroid remnant ablation?
Takes 2 days
Has severe contact precautions
What is involved in regular follow up post-thyroid cancer?
Measuring TSH (want to keep low)
Measuring tumour markers (calcitonin/thyroglobulin)
