Thyroid carcinoma Flashcards
What is meant by differentiated thyroid carcinoma (DTC)?
This is the name given to both papillary and follicular carcinoma as they both have a well-differentiated histological appearance
How does female risk of thyroid carcinoma changes with age?
Risk increases from 15-40 and then plateaus
How does male risk of thyroid carcinoma change with age?
Risk increases steadily with age
What has a strong association with thyroid carcinoma?
Radiation (Clusters found in areas of nuclear incidents)
What have a weak association with thyroid carcinoma?
Thyroid adenomata
Chronic TSH elevation
Increased parity
What common carcinogenic factors have no association with thyroid carcinoma?
Diet
Other malignancy
Family history
Smoking
What is the most common type of thyroid cancer?
Papillary carcinoma
What are the 4 main types of thyroid carcinoma?
Papillary
Follicular
Anaplastic
Medullary
What are some conditions associated with papillary carcinoma?
Hashimoto’s thyroiditis
Ionising radiation exposure
What are some genetic associations with papillary carcinoma?
- MAP kinase pathway activation mutations
- RET or NTKR1 rearrangements
- BRAF point mutations
- Ras mutations
Describe the histology of papillary carcinoma
Most take up iodine and secrete thyroglobulin and are TSH drive
They are usually solitary nodules on the thyroid
They are derived from the follicular epithelium
They can be multifocal, cystic and possibly calcified (Psammoma bodies)
They will most commonly spread through lymphatics and sometimes spread through the blood
How will papillary carcinoma usually present?
Thyroid or cervical lymph node mass
Local effects:
- Hoarseness
- Hysphagia
- Cough
- Dyspnoea
Wha is the 10 year mortality for papillary carcinoma?
<5%
What is the 2nd most common thyroid cancer?
Follicular carcinoma
Who is more at risk of follicular carcinoma?
Females
Iodine deficient areas
What are some genetic associations of follicular carcinoma?
- PI2K/AKT pathway mutations
- Ras mutations
- Pax8 and PPARy1 translocations
How will follicular carcinomas usually present?
Single nodule, which is slow growing, painless and non-functional
What are the 2 main classes of follicular carcinoma?
Widely invasive
Minimally invasive
Describe the histology of widely invasive follicular carcinoma
- More solid architecture
- Less follicular architecture
- More mitotic activity
Describe the histology of minimally invasive follicular carcinoma
- Most common
- Well-differentiated follicular architecture
- May have a part surrounding capsule
- Difficult to distinguish from adenoma
How do follicular carcinomas usually metastasise?
Haematogenous to lungs, bones, liver and brain
Rarely lymphatic
How do papillary carcinomas usually metastasise?
Lymphatics
Rarely haematogenous
How will follicular carcinoma present?
Thyroid or cervical lymph node mass
Local effects:
- Hoarseness
- Dysphagia
- Cough
- Dyspnoea
What is the 10 year mortality of follicular carcinoma?
<5%
What are anaplastic carcinomas?
Undifferentated and aggressive tumours derived from the follicular epithelium
How do anaplastic carcinomas usually occur?
De novo or due to de-differentiation of another cancer
What are some genetic associations of anaplastic carcinoma?
- p53 mutations
- ß-Catenin mutations
- MAP kinase pathway activation mutations
- RET or NTKR1 rearrangements
- BRAF point mutations
- Ras mutations
How will anaplastic carcinoma usually present?
Rapid growing thyroid mass
Cervical lymphadenopathy
Local effects:
- Hoarseness
- Dysphagia
- Cough
- Dyspnoea
How are anaplastic carcinomas investigated?
TSH levels
USS
US-FNA or biopsy
How is anaplastic carcinoma managed?
Total thyroidectomy if resectable +/- adjuvant radiochemotherapy as needed
Do not respond to RAI
What are medullary carcinomas?
Tumours of the parafollicular cells which secrete calcitonin (C-cells)
What are the 3 types of medullary carcinoma?
Sporadic
MEN2A/B associated
Familial medullary carcinoma associated
At what age do MEN associated medullary carcinomas usually occur?
Very young patients
At what age do sporadic or familial associated medullary carcinomas usually occur?
Middle-aged adults (40-50)
How will sporadic medullary carcinoma usually present?
Solitary thyroid nodule
Local effects:
- Dysphagia
- Hoarseness
- Cough
- Dyspnoea
How will familial medullary carcinoma usually present?
Bilateral or multi-centric thyroid nodule
Local effects:
- Dysphagia
- Hoarseness
- Cough
- Dyspnoea
Describe the histology of medullary carcinoma
They are composed of spindle or polygonal cells, arranged into nests, trabeculae or follicles
Familial cases will have C-cell hyperplasia
What condition can be caused by medullary carcinoma?
Amyloidosis (Abnormally folded calcitonin)
What are some paraneoplastic syndromes of medullary carcinoma?
Diarrhoea - VIP production
Cushing’s - ACTH production
What are some factors that increase prognosis of medullary carcinoma?
Young
Female
Smaller tumour confused to thyroid
What are some factors that decrease prognosis of medullary carcinoma?
Necrosis
Many mitoses
Squamous metaplasia
Small cell morphology
Familial forms
What are some investigations required in medullary carcinoma?
- Neck USS and FNA
- Measure serum base calcitonin
- 24 hour urinary metanephrines
- Further imaging to detect localised/advanced disease
- Check genetics for MEN
