Endocrine Neoplasia Flashcards
What is the key histology of the thyroid gland?
Thyroid follicular cells form circular edges around colloid = thyroid follicle
Colloid contains thyroglobulin which is secreted from follicular cells -> formation of T3 andT4
Parafollicular cells or C cells ->secrete calcitonin
Stroma
What is meant by a thyroid nodule?
How does it present?
A solitary thyroid nodule - unusual growth on thyroid (fluid or solid)
Palpable/visible swelling of the thyroid gland
Up to 10% incidence
Pressure symptoms
Pain
What is thyroid neoplasia?
How does it normally present?
Abnormal growth in the thyroid gland
Thyroid nodules are common
Benign : Malignant 10:1
Increased frequency with age
Solitary nodule > neoplastic
Solitary nodule in young person more likely to be cancerous than in older person
More common in female
What test should be done to identify thyroid malignancy?
Serum TSH
(as growth factor stimulate growth of thyroid tissue including cancer cells)
What factors are important to understand in a history surrounding the thyroid lump?
Duration of swelling
Risk factors - radiation to head/neck
Family history - MEN syndrome
Concerning features - rapid growth, pressure symptoms, hoarseness of voice (vocal cord paralysis)
Lump - fixed and hard, lymphadenopathy, signs of hyper/hypothyroidism
What is thyroid scintigraphy?
How to interpret it?
Type of nuclear imaging, uses a radiotracer that mimics Iodine
Taken up by thyroid gland - shows activity of te thyroid gland in terms of T3/4 production
Hot nodules - more intense signal - increased uptake
Cold nodules - less intense signal - reduced uptake.
What type of thyroid nodule is more common hot or cold?
Cold nodules are more common (85%) compared to hot/functional nodules (15%)
How does hot(functional) or cold thyroid nodule relate to cancer risk?
Cold - 15% malignant
Hot - 5% malignant
Note patients are more likely to have a cold nodule, cold nodules are more likely to be malignant that hot.
What is the gold standard test for evaluation of a thyroid nodule?
Fine needle aspiration cytology (FNAC)
Safe, accurate and cost effective
When/how is a fine needle aspiration done for a thyroid nodule?
For nodules >1cm
Is palpation or ultraound guided
Uses a 23-27 gauge needle
What are the signs on cytology of thyroid cancer?
Look at thyroid follicular cells
Bubble in nucleus = intranuclear inclusion
Line through nucleus = nuclear groove
What are the different rating for thyroid cytology results?
Thy1 to Thy5
Thy1 - non diagnostic (not enough cells) cancer risk 5 to 10%
Thy2 - benign, up to 3% risk
Thy3a - insignificant atypia (up to 30% risk)
Thy3f - follicular neoplasm - up to 40% risk
Thy4 - suspicious for malignancy - up to 75% risk
Thy5 - malignant up to 99% risk
Give an example of a benign thyroid neoplasia
Thyroid adenoma / follicular adenoma
Give some examples of malignant thyroid neoplasia
Follicular thyroid carcinoma
Papillary thyroid carcinoma
Medullary carcinoma
Anaplastic carcinoma
What is the most common malignant thyroid tumour?
Papillary thyroid carcinoma = 85%
How does the lump in papillary thyroid carcinoma present?
Solitary or multifocal
Well-circumscribed or encapsulated or infiltrative
Cauliflower like gross appearance
What is the histological appearance of a papillary thyroid carcinoma?
Branching Papillae - finger like projections lined by cancerous cells
Cancerous cells appear empty
On closer inspect have a circular ring to the nucleus (intranuclear inclusions)
What is the clinical course of papillary thyroid carcinoma?
Tends to metastasise through the lymphatic channels -> cervical lymph nodes
Excellent prognosis with a 95% 10 year survival
What are the treatment options commonly used for papillary thyroid carcinoma?
Surgery for >1cm
If less than 1cm - papillary microcarcinoma may use active surveillance.
How does a thyroid adenoma/follicular adenoma lump present?
Benign
Solitary and painless
Encapsulated - does NOT invade surrounding capsule/vasculature
Large = pressure symptoms and difficulty swallowing
How does thyroid adenoma/follicular adenoma appear on diagnostics?
On radioiodine scan - is a cold nodule
Fine needle aspiration - Thy3f
What is the typical treatment for a thyroid adenoma/follicular adenoma?
Surgical excision with capsule intact
How common are follicular carcinoma of the thyroid?
5-15% of thyroid carcinoma
How does follicular carcinoma present on exam and investigation?
Solitary nodule, slowly enlarging
Frequently cold on scintigraphy, but may appear warm - requires FNA
How to differentiate between follicular adenoma v follicular carcinoma on cytology/histology?
On histology both show colloid containing follicles uniform nuclei, encapsulated
In histology adenoma does not show capsular and vascular invasion
Carcinoma - shows capsular and vascular invasion (mushroom-shaped)
Must have histology and FNAC will not show a difference
Is this a follicular adenoma or carcinoma?
How can you tell?
Adenoma
Intact capsule surrounding the tumour - no capsular or vascular invasion
In reference to the histology below, how do you differentiate between a follicular adenoma/carcinoma?
Adenoma = A = respects thin capsule boundaries
Carcinoma = B = mushroom shaped invasion of tumour (more purple) into surrounding capsule and tissue (Light pink)
What is the clinical coures of follicular thyroid carcinoma?
Tends to metastasise through the blood vessels to the bone, lungs and liver. (commonly lumps on scalp)
Prognosis depends on extent of invasion and stage at presentation
Widely invasive <10yrs
Minamally invasive - >90% survival at ten years
What is the most common treatment for follicular thyroid carcinoma?
Total thyroidectomy
Radioactive iodine for Mets
What is meant by anaplastic carcinoma of the thyroid?
“Lack of differentiations” to form backwards
Agressive tumour - mean age of honest is 65yrs.
Invasion of neck structures - dyspnea, dysphagia, hoarness and cough
Metastatsis
Mortality rate near 100%
What carcinoma of the thyroid is this?
Anaplastic carcinoma of the thyroid
High pleomorphic, multinucleated cells
High grade tumour
What is medullary carcinoma of the thyroid?
Originates from parafollicular cells or C cells
Neuroendocrine tumour
Increase calcitoninc levels
70% are sporadic rest are associated with MEN2A/2B
What thyroid carcinoma is this?
Salt and pepper chromatin
Forms sheets and layers
Calcitonin deposits (pink material ) in the stroma are termed amyloid.
Medullary thyroid carcinoma
What is multiple endocrine neoplasia?
MEN syndrome
Autosomal dominant - genetic disorder
Causes proliferative/neoplastic disorders in multiple endocrine organs
Starting asymptomatic hyperplasia of organs
Tumours occur at younger age
Can affect multiple organs - simultaneous or different times
What are the two different types of MEN syndrome?
MEN 1
MEN 2A/2B
What are the genetics of MEN 1 syndrome?
Affects the menin gene on chromosome 11
Inactivating mutation
What is the genetics of the MEN2A/2B syndrome?
Affects the RET protoncogene
Chromosome 10
Gain of function mutation.
What endocrine organs are commonly affected in MEN 1?
Pituitary
Parathyroid
Pancreatic endocrine
What are the endocrine organs commonly affect in MEN2A syndrome?
Medullary thyroid
Parathyroid
Bilateral phaeochromocytoma
What are the endocrine organs commonly affected in MEN 2B syndrome?
Neuromas (nerves in mouth, lips, tongue)
Medullary carcinoma of the thyroid
Phaeochromocytoma
