Thyroid Pathology Singh Flashcards
Where is thyroglobulin stored and made, and what does it do?
- Tg is made and stored in colloid
- Iodide gets transported to the cell and incorporated into Tg making iodinated tyrosines
- Tg gets endocytosed and cleaved to release T3 and T4
How does T3 impact TSH and GH?
Incr. Growth hormone and decresase TSH
Hyperthyroidism (Thyrotoxicosis) symptoms?
- perspiration
- facial flushing
- weight loss
- palpitation/tachy
- diarrhea
- nervousness/excitablitiy/restlessness/insomnia/emotional instablity
- exopthalmos (graves disease not just hyperthyroidism)
What causes primary hyperthyroidism?
- Grave’s disease
- Hyperfunctioning multinodular goiter
- Hyperfunctioning thyroid adenoma
most common cause of hyperthyroidism
What would cause secondary hyperthyroidism?
Pituitary adenoma
If TSH is low would this indicate primary or secondary hyperthyroidism?
Primary because the thyroid hm is negatively inhibiting TSH
Apathetic hyperthyroidism?
- Older adults with masked symptomatology
- Unexplained weight loss
- CV dz
What is Thyroid storm? What is the scoring system?
- Sudden severe onset:
- fever
- cardiac → CHF or tachy
- GI → diarrhea, jaundice, pain
- Precipitating history:
- pregnancy
- hemithyroidectomy
- drugs such as amiodarone
Burch Wartofsky Score
How do you treat thyroid storm?
- Beta blocker (Propranolol) to treat the manifestations
- Treat the underlying disease
- high dose iodide
- thionamide
- radioiodine ablation
- surgery
Graves disease diagnostic triad?
- Hyperthyroidism with gland enlargement
- Infiltrative opthalmopathy
- Pretibial myxedema
How does Graves disease work?
- Thyroid stimuolating antibodies bind TSH receptor and increase T3 and T4 release
- Exopthalmos occurs bc fibroblasts become stimulated by these AB’s and increase retro orbital CT mass
If you see resorption droplets in histology what would this indicate?
- Graves disease
- intracytoplasmic droplets appear representing colloid in endocytotic vesicles
What are the expected labs for Grave’s disease?
- T3 and T4 → high
- TSH → low
- TSI → high
Congenital hypothyroidism (“cretinism”) symptoms, where is it seen, what causes it?
- early infancy/childhood
- imparied mental dev, decrease growth, coarse facial features, umbilical hernias
- Seen in endemic areas without iodine supplementation
- depends on time of onset in mother while pregnant
- Can be result of genetic alterations in normal thyroid metabolic paths
What causes secondary hypothyroidism?
- Pituitary failure
- Hypothalamic failure
both are rare, and everything else is a primary cause
Hypothyroidism (myxedema) in the adult/older child symptoms?
- edema of face/eyelids
- coarse cool dry yellowish skin
- dry brittle hair
- slow cerebration
- weight gain
- cold intolerance
- cardiac effect → low output, hypercholesterolemia
Hashimoto’s thyroiditis?
- most common thyroiditis in iodine sufficient areas, it is autoimmunity against thyroglobulin and thyroid peroxidase
- diffuse painless enlargement of thyroid
Hashimoto thyroiditis progression?
Immune mediated insult → Hyperactivity & elnargement → follicular cell exhaustion
Thisis called hashitoxiocosis
What is this
- Hashimoto thyroiditis → thyroid is mildly enlarged and painless and path shows lymphocytic infiltrate with germinal centers
- Atrophic follicle cells with eosinophilic change
- Hurthle cell metaplasia
what is this
Left → hashimoto
Right → graves
What is Granulomatous thyroiditis?
- AKA De Quervain’s thyroiditis
- painful granulomata
- possibly viral in origin
- sometimes lumped with subacute thyroididits
- assoc. with HLA B35
What is Riedel Thyroiditis?
- Fibrosing process extending from thyoid into adjacent tissues
- you can see invasion into skeletal muscle
- surgeons think it could be cancer as it feels like cement and is a difficult thyroidectomy
- you can see invasion into skeletal muscle
- Excessive fibrosis but you also see lymphocytes and plasma cells (plasma cells → perinuclear hoff)
Fill in blanks
Diffuse nontoxic goiter
- result of thyroid metabolism issues
- it is an endemic goiter due to iodine deficiency or excess ingestion of thyroid hormones such as broccoli, cauliflower cabbage radish, cassava root
- thyroid swells to get to a euthyroid state
Multinodular goiters?
- Hyperplasia
- can produce the same mass effect as difffuse goiters
- can become massive
Describe follicular adenomas
- Clonal population of folllicular cells with thyroid autonomy
- Benign but need to rule out follicular carcinoma and papilllary carcinoma
Describe the histo of papillary thyroid carcinioma and diagnostic features?
- Papillary architecture
- Psammoma bodies
- RET-PTC mutations and BRAF mutations
- Diagnostic features are the enlarged nuclei wit h”clear” appearance → “Orphan Annie Eye Nuclei”
Describe the variant, Follicular variant of PTC.
- Follicular architecture but nuclear features of papillary carcinoma
- fewer cases have RET-PTC or BRAF
- More cases with RAS mutations
- similar to follicular carcinoma and adenoma
Tall Cell Variant of Papillary Carcinoma
- older patients and aggressive
- can be COD even if contained to thyroid
Diffuse sclerosing variant of Papillary carcinoma
- Kids and young adults
- Higher incidence of mets
- has high survival rate of 93% at 10 years
Follicular carcinoma commonality and mutations?
- Invasive properties
- less common than papillary carcinoma
- more common in areas with goiter from iodide deficiency
- PAX8/PPARG
Describe the histology of Follicular carcinoma
- Invasive properties seen with invasion of the capsule (mushroom) and Angioinvasion
What is anaplastic carcinoma?
- uncommon (~5%) very deadly cancer that occurs in older patients
- presents with mass effect and patients usually die within a year of local invasion
What are Medullary carcinomas of the thyroid?
- Neuroendocrine carcinoma derived from C cells
- blue cells with dispersed chromatin
- amyloid can be present
- C-cell hyperplasia → stain
