Goitre, thyroid nodules and cancer Flashcards
What is a goitre
an enlarged thyroid gland and may be diffuse or nodular
A patient presents with a goitre. Give a differential
Graves' disease Multinodular goitre solitary adenoma thyroiditis Hashimoto's thyroiditis Simple goitre Malignancy (thyroid carcinoma, lymphoma Riedel's thyroiditis
What sex are more prone to goitres
Females
Prevalence of goitres increases with what 3 things
age
iodine deficiency
previous exposure to ionising radiation
Where are the most important goitrous areas in th world
Himalayas and the Andes
What features in the history raise the suspicion of malignancy
Age 60
recent rapid enlargement of a thyroid nodule
dysphagia, dyspnoea, hoarseness, stridor
Family history of thyroid cancer or MEN (multiple endocrine neoplasia)
History of exposure to radiant
lymphadenopathy
Hashimoto’s thyroiditis
What tests should be requested to exclude thyrotoxicosis
TSH and free T4
Serum thyroglobulin levels are increased in what type of nodules
Benign and malignant nodules
What should be measured when medullary cell carcinoma is suspected
Calcitonin
What test should all patients with a thyroid nodule have
A fine needle aspiration for cytological examination
What test is required if there is a high suspicion of malignancy
Ultrasound-guided fine needle aspiration
MEN2, suspicious ultrasound features, presence of cervical lymph nodes
What scan should be carried out for all patients with suppressed TSH
Radioisotope uptake scan
Why is Technetium pertechnetate more commonly used than iodine
Cheaper and more readily available
What should patients with suspicious or malignant cytology be offered
Surgery
What is the most common form of thyroid carcinoma
Papillary
What is the second most common form of thyroid carcinoma
Follicular
What genes are papillary carcinomas associated with
rearrangement of RET and NTRK1 and the formation of chimeric genes
In what populaiton is papillary thyroid cancer most prevalent
young women (30-50 years)
How do papillary carcinomas metastasise
Lymphatics to regional lymph nodes and distantly to the lungs and bones
What are papillary carcinomas characterised by?
One or two layers of tumour cells surrounding a fibrovascular core Cells and nuclei are large and their cytoplasm has a GROUND GLASS appearance
What does follicular carcinoma show
follicular differentiation and capsular or vascular invasion - it is epithelium derived
When is the peak incidence of follicular carcinomas
between the ages of 40 and 60
How can the distinction between follicular adenoma and carcinoma be made
through histological identification of capsule and or vascular invasion
How do follicular carcinomas spread
Haematogenous - (lung and bones) rather than to regional lymph nodes
In what population does anaplastic carcinoma more frequently occur
In older patients (60-80 years
How do patients with anaplastic carcinoma present
Rapidly enlarging neck mass
How is anaplastic carcinoma spread
Haemoatgenous spread
The risk of thyroid lymphoma is increased in patients with what
autoimmune thyroiditis
What is the treatment for papillary and follicular carcinoma
Initial thyroidectomy postoperative TSH suppression with thyroxine and in high risk patients, postoperative radio-iodine ablation
Why should all patients receive thyroxine post operatively
to prevent hypoparathyroidism and minimise potential TSH stimulation of tumour growth
How does radio-iodine treatment work
It causes cell death by the emission of beta rays when the thyroid follicular cells take up the radio-iodine
Prior to a radio-iodine scan, thyroxine is stopped and replaced with what
Shorter acting triiodothyronine
What are some complications of radio=iodine
radiation thyroiditis painless neck oedema sialoadenitis tumour haemorrhage or oedema nausea
What is the treatment for anapaestic thyroid carcinoma
Total thyroidectomy with lymph node clearance chemotherapy and external beam irradiation
What are some poor prognostic factors in differentiated thyroid carcinomas
Age 45+, male, family history, tumour size, local extension, lymph node and distant metastases
What type of thyroid cancer has the poorest survival rate
Anaplastic carcinoma, then follicular then papillary
When do most recurrences of differentiated thyroid carcinoma happen
Within the first 5 years after initial treatment
Describe the serum thyroglobulin concentration if initial surgery and thyroid remnant ablation are successful
It should be very low
Patients with autoimmune thyroiditis have an increased risk for what type of cancer
Thyroid lymphoma
