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210 Cards in this Set
- Front
- Back
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pituitary and thyroid gland are similar how?
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both have lobes (intermediate lobe, etc.)
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pyramidal lobe of thyroid gland is a remnant of what?
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thyroglossal duct above the isthmus
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colloid is what?
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a collection of proteins
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fxn of thyroid gland can be inhibited by a variety of chemical agents, referred to as?
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goitrogens
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goitrogens do what?
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they suppress T3 & T4 synthesis
TSH level increases get hyperplastic enlargement of gland |
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antithyroid agent, propylthiouracil inhibits what?
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inhibits oxidation of iodide & blocks production of thyroid hormones
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________ inhibits peripheral deiodination of T4 into T3, thus ameliorating sxs of thyroid excess
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propylthiouracil
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______ blocks release of thyroid hormones, thus can be given to pts w/ thyroid hyperfxn
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iodide
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iodides in large doses inhibit proteolysis of ____________, thus thyroid hormone is not released into________
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thyroglobulin
blood (even when synthesized & incorporated w/in increasing amts of colloid) |
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ectopic thyroid tissue is MC located where?
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at the base of tongue (lingual thyroid)
or other sites ABNL high in neck |
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what % of pts w/ ectopic thyroid have no other fxning thyroid?
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70%
before removing ectopic "mass" confirm w/ thyroid scan, FNA or biopsy |
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excessive descent of thyroid tissue leads to what?
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substernal thyroid glands
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thyroid descent tract is pseudostratified columnar or stratified squamous lined & usually obliterated, it passes thru ______
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hyoid bone
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____ can be seen anywhere along the thyroid descent tract
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cysts
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excessive descent of thyroid tissue may occur as low as the _______
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diaphragm (rare)
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external fistula is acquired or congenital? (RE: thyroid gland)
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acquired
(tract does not NLLY communicate w/ the skin) |
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what midline lesion is d/t persistent sinus tract connected to foramen cecum or suprasternal notch, or blind tubular structure inf to hyoid bone?
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the thyroglossal duct
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70% of ________________ often present as infxn in children age 5+ yrs
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congenital neck cysts
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thyroglossal ducts are usually detected when?
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in childhood, occasionally in adults
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thyroglossal duct is rarely assoc. w/ what?
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papillary thyroid carcinoma
(even if CA present, excellent prognosis after excision) |
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DDX of thyroglossal cyst?
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dermoid cyst
lymph node branchial cleft cyst ectopic thyroid ST tumors |
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thyroid nodule in neck anatomically separate from thyroid gland?
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parasitic nodule
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parasitic nodule is not assoc. w/ ________
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lymph nodes
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parasitic nodule may be connected to thyroid gland by thin fibrous strand of vascular tissue or may get its vascular supply from where?
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from surrounding tissue separate from thyroid gland
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22q11 deletion syndrome, velo-cardio-facial syndrome
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DiGeorge syndrome
del (22) detected by FISH |
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DiGeorge syndrome is d/t what?
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arrested development of 3rd & 4th branchial pouches
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in DiGeorge syndrome...there's absence of what 3 things & what defects?
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1. C cells
2. thymus 3. paraTH glands ...4. conotruncal cardiac defects |
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what is the MC manifestation of thyroid dz?
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goiter
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what do diffuse & multinodular goiters represent?
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they reflect impaired synthesis of thyroid hormone
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impaired synthesis of thyroid hormone is most often caused by what?
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dietary iodine def'y
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impaired synthesis of thyroid hormone leads to what lab finding?
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leads to compensatory rise in serum TSH level
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presence of goiter, think??
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rise in serum TSH level
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rise in serum TSH level causes what?
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hypertrophy & hyperplasia of thyroid follicular cells, ultimately, gross enlargement of thyroid gland
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if pt. is able to overcome the hormone def'y w/ hi TSH level = what?
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euthyroid
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goitrous hypothyroidism may come from what?
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severe congenital biosynthetic defect or endemic iodine def'y
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degree of thyroid enlargement is proportional to what?
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to level & duration of thyroid hormone def'y
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nontoxic, colloid goiter
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simple goiter
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longstanding simple goiter
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multinodular goiter
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endemic simple goiter is seen in what 2 areas?
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1. mountainous areas (low iodine intake)
2. where foods integral to diet interfere w/ iodine uptake (cassava, turnips, cabbage) |
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which type of simple goiter is less common?
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sporadic (than endemic)
seen in young, F>>M |
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which type of goiter is most frequently mistaken for neoplasia form of thyroid dz?
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multinodular
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findings in multinodular goiter
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uneven follicular hyperplasia
generation of new follicles uneven accumulation of colloid rupture of follicles & vessels w/ hemorrhages scarring, & sometimes calcifications |
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what 2 things may contribute to nodularity of goiter?
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1. scarring adding to stress
2. preexisting stromal framework enclosing areas of expanded parenchyma |
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thyroid on micro
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follicular cells surrounding colloid
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multinodular goiter, see what 2 things?
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calcification, hemorrhage
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in multinodular goiter, what structures can project into the cystic areas?
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pseudopapillary & truly papillary structures (Sanderson's polsters)
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low TSH
high free T4 normal TRH stim test |
primary hyperTH
(intrinsic thyroid abnormality) |
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high TSH
abnormal TRH stim test |
2ndary hyperTH
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low TSH <0.1
normal T3 & T4 |
subclinical hyperTH
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T3 hyperTH 1-4%
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low TSH
high free T3 normal free T4 |
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what is assoc. w/ early tx of hyperTH w/ antithyroid drugs?
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T3 hyperTH
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T4 hyperTH
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high T4
normal T3 |
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T4 hyperTH can be d/t what 4 things?
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1. primary hyperTH causes
2. iodine 3. amiodarone 4. pregnancy (2%) |
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tx for hyperthyroidism?
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-beta-blockers for sxs
-thionamide-type drugs to block new hormone synthesis -iodine to block release of T4/T3 -radioactive iodine to destroy thyroid tissue |
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what tx for hyperTH blocks release of T4/T3?
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iodine!
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2 autoimmune disorders of the thyroid?
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Graves dz (hyperTH)
Hashimoto dz (hypoTH) |
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graves dz
triad of clinical findings: |
1. enlargement of thyroid
2. exophthalmos (infiltrative ophthalmopathy) 3. pretibial myxedema (infiltrative dermatopathy) |
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a feature seen only in graves dz?
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TRUE thyroid ophthalmopathy assoc. w/ proptosis
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what is central to Graves dz pathogenesis?
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TSH receptor antibodies
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what are the 3 types of TSH R Abs?
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TSI thyroid stimulating immunoglobulin
TGI thyroid growth stimulating immunoglobulins TBII TSH-binding inhibitor immunoglobulins |
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TSI is relatively specific for ______
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Graves dz
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TGI have been implicated in the proliferation of ________
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thyroid follicular epithelium
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TBII does what 2 things?
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1. prevent TSH from binding normally to R
2. mimic the action of TSH |
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why do some pts w/ graves dz spontaneously develop episodes of hypothyroidism?
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d/t coexistence of stimulating & inhibiting immunoglobulins in the serum of same pt
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hyperthyroidism on histo
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colloid lobules are dec or absent, have irregular form, 'scalloped'
involuted/convuluted edges can look like papillary carcinoma |
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hypothyroidism that develops in infancy or early childhood?
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Cretinism
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most hypothyroidism pts look relatively __________
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normal
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most cases of hypothyroidism are d/t what?
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Hashimoto's thyroiditis or iodine def'y
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hypothyroidism may cause what type of anemia?
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macrocytic, nonmegaloblastic anemia w/ NL RDW
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normal TSH
low T3 & T4 |
primary hypothyroidism
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causes of primary hypothyroidism
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destruction of thyroid (surgery, radiation, Hashimoto's thyroiditis, developmental)
interference w/ thyroid hormone synthesis (idiopathic, genetic, lithium, iodide, methimazole, PTU, iodine ingestion, iodine def'y, chronic renal failure) |
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pituitary disorder causing reduced TSH secretion gives?
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2ndary hypothyroidism
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hypothalamic lesion causing reduced TRF secretion gives?
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tertiary dx hypothyroidism
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high TSH
NL T3 & T4 no clinical sxs of hypothyroidism |
subclinical hypothyroidism
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congenital hypothyroidism is usually d/t what?
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thyroid dysgenesis
rarely d/t inborn errors of metabolism |
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what are the sxs of congenital hypothyroidism?
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1. impaired development of skeletal system (short coarse facial features & protruding tongue)
2. severe mental retardation |
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maternal hypothyroidism may cause what? & why?
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severe mental retardation
bc maternal T3/T4 crosses placenta & is critical to brain development before fetal gland develops |
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what is the tx for congenital hypothyroidism?
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immediate hormone replacement
(tx after early childhood may not correct intellectual deficits) |
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what is the most sensitive screening test for hypothyroidism (has nonspecific sxs)?
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measurement of serum TSH level
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myxedema or Gull dz can be seen in what?
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hypothyroidism
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what is the MC cause of hypothyroidism in areas of world where iodine levels are sufficient?
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Hashimoto's thyroiditis
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pts w/ goiter & intense lymphocytic infiltration of thyroid (struma lymphomatosa)?
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Hashimoto's thyroiditis
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what are the variants of Hashimoto's thyroiditis?
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fibrous/sclerosing
fibrous atrophy juvenile cystic forms |
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hashimoto's thyroiditis is most prevalent in what age group & in what sex?
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45-65 yrs
MC in women 10:1 so, a dz of older women |
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a major cause of nonendemic goiter in children?
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Hashimoto's thyroiditis
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hashimoto pts demonstrate what?
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circulating antithyroid antibodies
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hashimoto's thyroiditis pts have inc risk for developing what?
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other concomitant autoimmune dzs
1. endocrine (DM1, autoimmune adrenalitis) 2. nonendocrine (SLE, MGravis, Sjogren syndrome, B cell NHL) |
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NL thyroid grossly?
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has colloid, it weeps when cut, beefy red appearance
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looks like fish flesh (full of lymphocytes)??
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hypothyroid (grossly)
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fragments of colloid
involuted in B cells surrounded by T cells?? |
Hashimoto's dz
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Hurthle cell metaplastic response is part of what dz?
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Hashimoto's dz
(some cells are swollen on histo) |
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adult w/ painless, gradual thyroid failure d/t autoimmune destruction?
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Hashimoto's dz
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anti-TSH antibodies _____ the TSH R in Hashimoto's dz but ____ the TSH R in Graves' dz
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block
stimulate |
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what HLA is goitrous form of Hashimotos?
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HLA- DR5
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what HLA is atrophic form of Hashimotos?
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HLA-DR3
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autoimmune thyroiditis spectrum?
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is from grave's to hashimoto's
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granulomas will be seen in the thyroid when __________________
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when there's entrapped material
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autoimmune thyroiditis may be d/t disturbance in what?
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suppressor T cells
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autoimmune thyroiditis occurring w/in 1 yr after delivery
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post-Partum thyroiditis
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what is present in 44% w/ Grave's dz, assoc w/ smoking?
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post-partum thyroidits
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what % of post-partum hypothyroidism pts persist?
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56%
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on micro: focal aggregates of lymphocytes in inter or intralobular fibrous tissue, no oxyphilic metaplasia, no follicular atrophy, no follicular disruption
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focal lymphocytic thyroiditis
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5-20% of adult autopsies (more in elderly women) show what?
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focal lymphocytic thyroiditis
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FLT is assoc w/ low levels of _________, lacks ___________ and may be early/mild form of _________
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antithyroid Abs
clinical sxs autoimmune thyroiditis |
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on micro:
follicle developing w/ center portion more expanded More B cells than T cells!!! |
FLT
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sudden onset of pain, glandular enlargement, comes via blood or direct seeding from URIs?
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infectious thyroiditis
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risk factors for infectious thyroiditis?
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malnourished infant
debilitated elderly immunosuppression trauma |
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suppurative cases of infectious thyroiditis may be assoc. w/ ___________
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pyriform sinus fistula
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aka multifocal granulomatous thyroiditis
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palpation thyroiditis
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85%+ of surgically resected thyroids but no clinical significance?
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palpation thyroiditis
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palpation thyroiditis is more often assoc. w/ ____________ than autoimmune thyroiditis
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goiter
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palpation thyroiditis on micro?
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multiple small granulomas centered in disrupted follicles
composed of lymphocytes (usually T cells) usually no necrosis no neutrophils |
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densely fibrotic inflammatory process involving thyroid gland & adjacent neck tissue
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Riedel's thyroiditis
aka Riedel's struma, fibrous thyroidits |
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what clinically resembles carcinoma, is assoc.w/ inflammatory fibrosclerosis/multifocal systemic fibrosclerosis (mediastinal or retroperitoneal fibrosis, sclerosing cholangitis, inflammatory pseudotumor of orbit)?
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Riedel's thyroiditis
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what % of Riedel's thyroiditis have antithyroid antibodies?
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65%
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inflammation of thyroid gland w/ granulomas
aka de Quervain's thyroiditis or granulomatous thyroiditis |
subacute thyroiditis
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MC cause of thyroid PAIN?
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subacute thyroiditis
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3 phases of subacute thyroiditis?
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1. hyperthyroidism
2. hypothyroidism (1% remain permanent) 3. recovery & resolves in 6-8wks |
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75% in women, usually 30-50yo
assoc. w/ HLA-Bw35, rarely familial |
subacute thyroiditis
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etiology of subacute thyroiditis may be what?
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systemic viral infxn
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sxs of subacute thyroiditis?
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odynophagia
sore throat thyroid region tenderness fever fatigue malaise |
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__________ is PAINFUL, pt. says 'my thyroid hurts', thus not hashimotos
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subacute thyroiditis
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what is a characteristic feature of subacute thyroiditis on histo?
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aggregates of neutrophils in the follicles; multinucleated giant cells are rare
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"cold" nodules on thyroid scan
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incidental benign lesions (appear as masses)
i.e. colloid cysts -->distinguish from carcinoma |
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a solitary, well-circumscribed nodule, w/ massive proliferation of follicular cells on micro
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follicular adenoma of the thyroid
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adenoma vs. multinodular goiter
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adenoma:
1. produce more compression of adj thyroid parenchyma 2. have a well-formed capsule (both have multiple nodules on their cut surface) |
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in pts who present w/ thyroid nodules, what's of major concern?
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neoplastic dz
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overwhelming majority of solitary nodules of thyroid prove to be ________ or __________
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benign
follicular adenomas |
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solitary nodule are more likely to be __________ than are multiple nodules
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neoplastic
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nodules in which pts are more likely to be neoplastic?
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in younger
in male pts |
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take up radioactive iodine in imaging; "hot" nodules are more likely to be?
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benign!
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cold nodules could be what?
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carcinoma!
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what % are papillary CA?
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75-85% of thyroid CA
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what % are follicular CA?
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10-20%
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what % are medullary CA?
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5%
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what are <5% of thyroid CA cases?
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anaplastic CA
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painless nodule/mass in neck or cervial node
cold on scan ??? |
papillary CA
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dx papillary CA by?
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FNA
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at presentatin what % of papillary CA in thyroid only? in nodes too? in nodes only?
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67% in thyroid only
13% in thyroid & cervical nodes 20% in nodes only |
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nodal mets of paillary CA may undergo cystic change & thus resemble what?
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branchial celft cysts
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what is assoc. w/ a more indolent course of papillary CA?
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RET/PTC oncogene alterations
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does cervical nodal involvement affect prognosis of papillary CA?
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NO!
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who has poorer prognosis w/ papillary CA?
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age 40+ or elderly, male?, local invasion
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to detect recurrent dz (papillary CA)?
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measure thyroglobulin in FNA from LNs in pts w/ hx of papillary thyroid CA
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follicles w/ nuclear features of PTC
more indolent than follicular CA |
follicular PTC variant
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PTC tumors most often arise in whom?
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in middle-aged females
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orphan annie inclusions
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papillary CA
(eyes w/ no pupils) |
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on histo:
pure follicular architecture papillary CA nuclei prognosis: lower LN mets more favorable encapsulation |
follicular PTC variant
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papillary neoplasm on histo
see grooves in nuclei |
follicular variant PTC
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see infolding
affects older pts extrathyroidal extension more common worse/poor prognosis which variant of PTC? |
Tall cell variant PTC
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follicular differentiation
no papillary nuclear features solitary, not occult "cold" on scan |
follicular CA of thyroid
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older age than papillary CA
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follicular CA of thyroid
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risk factors for follicular CA of thyroid?
|
radiation exposure
iodine def'y older age (not from preexisting adenoma) |
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what %s give distant mets in invasive follicular CA of thyroid?
|
50% if vascular & capsular invasion
75% if local invasion & vascular or capsular invasion |
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give me 3 'encapsulated' classes of follicular CA?
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1. w/ capsular invasion only
2. w/ limited vascular invasion (<4 vessels) 3. w/ extensive vascular invasion (>4 vessels) |
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what are the poor prognostic factors of follicular thyroid CA?
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distant mets, age >45yrs, large size, extensive vascular invasion, extrathyroidal extension, poorly differentiated or widely invasive tumors
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follicular type appearance
no orphan annies etc. |
follicular carcinoma
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neuroendocrine tumore derived from __________ of ultimobranchial body of neural crest, which secrete __________ = medullary carcinoma
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C cells (parafollicular cells)
calcitonin |
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5-10% of thyroid carcinomas are what?
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medullary carcinoma
|
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2 types of medullary carcinoma?
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1. sporadic 75-80%
2. hereditary |
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which medullary carcinoma?
solitary, paraneoplastic syndromes, dysphagia & hoarseness from tumor bulk |
sporadic type
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which medullary carcinoma?
younger pts, d/t MEN2A or 2B syndromes, familial MTC, VHL, or NF, bilateral, multicentric w/ C cell hyperplasia |
familial type (screen serum calcitonin or peripheral blood RET oncogene analysis)
|
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mets may be initial presentation of dz & usually contain amyloid?
|
medullary thyroid Ca
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which form of medullary Ca has the poorer prognosis?
|
sporadic form!
|
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5 yr survival w/ medullary thyroid Ca?
|
86%
|
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high serum calcitonin & chromogranin A levels screen for what?
|
medullary thyroid Ca
|
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to monitor for recurrence of MTCa, can use what?
|
calcitonin levels
|
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when is total thyroidectomy the TOC for MTC?
|
~ familial forms, w/ cervical lymphadenopathy for node pos. pts
|
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widespread invasion
on gross, see almost no NL thyroid present |
MTC
|
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brown cells b/t follicles on thyroid specimen histo?
|
calcitonin (MTC)
|
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aka undifferentiated (high grade) carcinoma of thyroid gland, carcinosarcoma, sarcomatoid carcinoma
|
anaplastic carcinoma of thyroid
|
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arises as anaplastic transformation of papillary, follicular or Hurthle cell carcinoma, core conserved mutations
rapidly enlarging, bulky neck mass causing hoarseness, dysphagia, dyspnea |
anaplastic carcinoma of thyroid
|
|
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resistant to all txs, death usually w/in 1yr??
|
anaplastic thyroid carcinoma
(mean survival 6 mos.) <10% make it to 2yrs |
|
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what methods are utilized for clinical staging?
|
inspection/palpation of gland & LN
indirect laryngoscopy (look at vocal cords) imaging w/o iodine contrast preoperative U/S for papillary thyroid CA |
|
|
why no iodine contrast when imaging carcinoma for staging?
|
iodine contrast delays use of I-131 for tx
|
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TNM
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tumor nodes mets
|
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3 components of pathologic staging
|
1. clinical staging
2. histologic exam 3. surgeon's description of gross unresected residual tumor |
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staging TX
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primary tumor cant be assessed
|
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staging T0
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no evidence of primary tumor
|
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staging:
T1 T2 T3 |
limited to thyroid, <2cm
limited to thyroid, >2cm <4cm limited to thyroid, >4cm OR w/ minimal extrathyroid extension |
|
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staging:
T4a T4b |
any size tumor beyond capsule invading subQ ST, larynx, trachea, esophagus or recurrent lar. N
tumor invading prevertebral fascia or encasing carotid A or mediastinal vessels |
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T4 is _________ by definition
|
anaplastic!
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anaplastic carcinoma; all are considered ____ tumors
|
T4
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surgically unresectable anaplastic CA
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T4b extrathyroidal anaplastic
|
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surgically resectable anaplastic CA
|
T4a intrathyroidal anaplastic
|
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6+ LNs
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selective neck dissection
|
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10+ LNs
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radical or modified radical neck dissection
|
|
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what 3 are regional LNs of thyroid?
|
1. central compartment
2. lateral cervical 3. upper mediastinal LNs |
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NX
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regional LNs cant be assessed
|
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N0
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no regional LN mets
|
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N1
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pos. regional LN mets
|
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N1a
N1b |
a. mets to level VI LNs (pretracheal, Delphian etc.)
b. mets to unilateral, bilateral, or contraL cervical or sup. mediastinal LNs |
|
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MX
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distant mets cant be assessed
|
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M0
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no distant mets
|
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M1
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distant mets
|
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papillary or follicular
stage 1 under 45yrs |
M0
|
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papillary or follicular
stage 1 over 45yrs |
T1N0M0
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papillary or follicular
stage 4c over 45yrs |
any T, any N, M1
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medullary carcinoma
stage 1 |
T1N0M0
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MTC
stage 2 |
T2N0M0
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anaplastic carcinoma- all cases are?
|
stage 4
|
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anaplastic
stage 4a |
T4a, any N, M0
|
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anaplastic
stage 4b |
T4b, any N, M0
|
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cold nodule DDX
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adenoma, papillary, follicular, cyst, carcinoma, lymphoma etc.
|
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benign, hot nodule DDX
|
adenoma, lymphocytic thyroiditis, multinodular goiter
|
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1-5% of thyroid tumors are?
|
thyroid gland lymphoma
|
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|
lymphoma, what type of nodule on scan?
|
COLD
|
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lymphoma is usually ___ cell in origin
|
B
|
|
|
primary tumor often arising in background of lymphocytic or Hashimoto's thyroidits after 20-30yrs??
|
thyroid gland lymphoma (particulary MALT type)
|
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|
MC subtype of lymphoma is?
|
diffuse large B cell lymphoma
|
