Thyroid and Parathyroid Pathology Flashcards
parathyroid cells types (3)
-Chief cells
-Oxyphillic cells
-Adipose cells
Chief Cells (3)
-Functional cells
-Parathyroid hormone synthesis and release
-Contain calcium sensing receptors
Parathyroid hormone (4)
Regulates serum calcium
- promoting release of calcium (and phosphate) from bone
- increases production of vitamin D to enhance intestinal calcium absorption
- Deceases calcium loss in urine, increases phosphate excretion
Parathyroid Adenoma (3)
> 85% of primary hyperparathyroidism
-10% hereditary
MEN1, MEN2, MEN4, HPT-JT
Parathyroid Adenoma vs Hyperplasia (4)
-Can look identical
-Conventional wisdom used to limit adenoma diagnosis to single entity “assuming normality/suppression of remaining glands”
-multiple adenomas in hereditary hyperparathyroidism (ie MEN etc)
-These are now recognised as adenomas, not hyperplasia
Hyperplasia (2)
-Primary hyperplasia thought to be v.rare
-Secondary / compensatory hyperplasia associated with physiological stimulus (ie low serum calcium, high serum phosphate, vit D deficiency)
Parathyroid Carcinoma (4)
<1% of primary hyperthyroidism cases
Can be familial - 15% of HPT-JT patients will develop
Can be sporadic
CDC73 (usually deletion / inactivation)
-Codes for parafibromin tumour suppressor protein
Diagnostic criteria for parathyroid carcinoma (5)
showing at least one of the following:
-Angioinvasion
-Lymphatic invasion
-Perineural invasion
-Invasion of adjacent structures/organs
-Regional/distant metastasis
Atypical Parathyroid Tumour (4)
looks weird but doesn’t meet the diagnostic criteria for parathyroid carcinoma
-Atypial cytological and architectural features, extension into capsule (but not through and into surrounding tissue)
-But not to be overused
-Parathyroid adenomas can have variation in appearance / occasional mitoses
Thyroid histology (3)
Follicular cells
Parafollicular Cells
Colloid
Thyroid physiology (4)
- hypothalamus releases hormone TRH which stims pituitary gland
2.pituitary gland releases hormone TSH which stims thyroid gland
3.thyroid gland makes the thyroid hormone T3 +T4
- As T3 + T4 are made they signal hypothalamus + pituitary to stop stimulating e.g. when T3 + 4 are adequate no more needs to be made
Thyroid Pathology (4)
Non-neoplastic=
-Inflammatory / Autoimmune
Neoplasia= Benign + Malignant
Non Neoplastic (3)
Multinodular goitre
Hashimotos thyroiditis
Graves disease
Multinodular goitre (5)
Also called nodular / multinodular hyperplasia
-Colloid goitre, hyperplastic nodule etc
-All represent the same process
Diffuse or nodular enlargement of the gland
Often very distorted
Hashimoto Thyroiditis (4)
Autoimmune process
-Elevated circulating antiperoxidase + antithyroglobulin antibodies
-Female predominance
Hyperplastic gland, usually 2-3X normal size, usually diffuse and symmetrical enlargement.
Hashimoto Thyroiditis path (3)
lymphatic infiltrate with germinal centre
-follicular trophy
-hurthle cell
Graves’ Disease (5)
Also known as diffuse hyperplasia
Autoimmune process
-Diffuse goitre, thyrotoxicosis, infiltrative opthalmopathy
From pathology perspective, important to know if patient has been treated
-Carbimazole can affect the way the cells look microscopically
Neoplasms- Benign (2)
Follicular adenoma
-Oncocytic adenoma
Neoplasms- Benignish (3)
NIFT-P
Thyroid Tumour of Uncertain Malignant Potential
Hyalising Trabecular Tumour
Neoplasms- Malignant (7)
Papillary carcinoma
Medullary carcinoma
Follicular carcinoma
-Oncocytic carcinoma
High grade follicular cell derived non-anaplastic thyroid carcinoma
-Poorly differentiated thyroid carcinoma
-Differentiated high grade thyroid carcinoma
Follicular adenoma (2)
Encapsulated neoplasm of thyroid follicular cells
Lacks capsular or vascular invasion
Oncocytic adenoma (4)
Previously known as Hurthle cell adenoma
Used to be a subtype of follicular adenoma, now has its own category
Oncocytic cells = swollen and pink
Encapsulated, non invasive
Follicular Carcinoma (4)
Looks like a follicular adenoma, but can have capsular invasion or vascular invasion
Or both
Can be widely invasive or minimally invasive, with or without vascular invasion
Additional variant “encapsulated with angioinvasion”
Oncocytic Carcinoma (3)
Used to be a variant of follicular carcinoma
Now has its own category
Criteria for malignancy same as follicular adenoma, but lesion must have dominant oncocytic cell component
Thyroid Tumours of Uncertain Malignant Potential (3)
Essentially used in situations where invasion is equivocal Or incomplete
For example, invasion into capsule, but not all the way through
Or tumour bulging into vessels but not fully into endothelial lined space
Papillary Thyroid Carcinoma (PTC) (2)
Most common thyroid malignancy
Multiple subtypes based on architecture, many have prognostic implications
PTC subtypes (11)
-Classic PTC
-Encapsulated PTC
-Diffuse sclerosing PTC
-Sold/trabecular PTC
-Warthin-like PTC
-Oncocytic PTC
-Spindle cell PTC
-PTC with fibromatosis/fasciitis-like/desmoid type stroma
-Tall cell PTC
-Hobnail PTC
-Columnar Cell PTC
PTC Molecular (3)
BRAF p.V600E mutations most common
-Have treatment implications
-Other genes which may be involved include RET, TERT promoter mutations, NTRK
Medullary Carcinoma (7)
C-cell derived neoplasm
Up to a quarter are associated with MEN2a or MEN2b
-Germline gain of function mutation in RET proto-oncogene
Often associated with increased serum calcitonon and or carcinoembryonic antigen (CEA)
Variable histological appearance
-Can show amyloid deposition
IHC often helpful – calcitonin positive along with neuroendocrine markers
Anaplastic Carcinoma (3)
Undifferentiated thyroid carcinoma
Characterised by aggressive progression and extremely poor prognosis- Usually fatal outcome
Usually thyroid IHC markers are lost, sometimes PAX8 is retained