Ch 3 Thyroid Pathology Flashcards
Role of u/s in imaging thyroid pathology?
-Locate nodules (intra/extra thyroidal)
-Describe appearance
-Determine other involvement (muscular, vasculature, lymph nodes, etc)
-Guide FNA/biopsy
-Follow up nodules for growth, new nodules, recurrence, post surgical, etc
What causes diffuse pathology of the thyroid gland?
-Inflammation/infection
-Thyroiditis (acute + chronic)
-Autoimmune (grave’s disease + hashimoto’s)
-Goiters
What causes focal nodules of the thyroid gland?
-Hyperplasia
-Adenoma
-Carcinoma
-Lymphoma
-Metastases
SF of focal nodules?
Variable
-Single or multiple
-Unilateral or bilateral
What procedure provides the diagnosis of benign vs malignant?
FNA cytology
Differentiate euthyroid, hyperthyroid + hypothyroid?
Euthyroid: normal functioning thyroid gland
Hyperthyroid: increased function
Hypothyroid: decreased function
What is the m/c thyroid function disorder?
Hypothyroidism (decrease in thyroid hormone production)
Differentiate b/w primary + secondary causes of hypothyroidism? Which is more common?
Primary:
-M/c
-Abnormality of the gland itself
-Decrease in T3/T4 = compensatory increased TSH
Secondary:
-Pituitary or hypothalamus failing to stimulate the normal thyroid function
-Decrease in TSH = decreased T3/T4
What is the m/c cause of primary hypothyroidism?
Worldwide: iodine
In iodine sufficient areas: hashimoto thyroiditis (aka chronic autoimmune thyroiditis)
Who m/c has primary hypothyroidism?
-Females, aged 45-65
-Associated with genetic predisposition, high iodine intake, selenium deficiency, smoking, chronic hepatitis C + other autoimmune diseases (such as sjogren syndrome, lupus + rhumatoid arthritis)
How is primary hypothyroidism diagnosed?
With bloodwork
What are the clinical manifestations/symptoms of hypothyroidism?
Depends on the severity (ranging from asymptomatic to myxedema coma)
M/c symptoms:
-Weakness/fatigue, dry skin, cold intolerance, hoarseness, weight gain, constipation, menstrual irregularities + decreased sweating
General SF of hashimotos thyroiditis
-Similar to Graves disease
-M/c diffusely abnormal echotexture*
-Hypervascular in early stage
SF of hashimotos thyroiditis in early, late + end stages?
Early:
-Increased size
-Coarse echotexture
-Hypo to normal echogenicity
Late:
-Fibrotic strands causing lobulations
End:
-Multinodular + fibrotic
-ill defined + heterogeneous
-Atrophic
An isthmus greater than how many cm AP indicates diffuse enlargement of the thyroid?
> 1cm AP
What causes thyrotoxicosis / hyperthyroidism?
Elevated levels of free T3 + T4 (this causes a hypermetabolic state)
Differentiate b/w primary + secondary hyperthyroidism?
Primary:
-Excess thyroid hormone is synthesized + secreted by the thyroid (ex. graves disease)
Secondary:
-Rare
-Due to an outside source (ex. TSH secreting pituitary adenoma)
What is the m/c cause of thyrotoxicosis?
Hyperthyroidism
What is the m/c cause of hyperthyroidism?
Graves disease
What is graves disease?
Autoimmune disease
(m/c in women of child bearing age)
Causes of graves disease?
-Hereditary
-Immune system
-Age
-Gender
-Stress
Pt’s with graves disease must present with 1 or more of the following symptoms:
-Hyperthyroidism
-Diffuse thyroid enlargement (goiter)
-Ophthalamopathy (protrusion of eyes)
-Graves dermopathy (pretibial myxedema)
(note: the general term myxedema refers to hypothyroidism, so we must be careful not to mix these terms up)
Clinical symptoms of hyperthyroidism/graves disease in adults?
-Severe wight loss
-Excessive sweating
-Heat intolerance
-Ophthalmopathy (bulging eyes)
-Enlarged thyroid (goiter)
-Tachycardia at rest
-Mood changes
-Dyspnea
-Nervous/anxiety
-Hand tremors/muscular weakness
-Menstrual irregularities (oligo or amenorrhea)
What happens if hyperthyroidism/graves disease gets left untreated?
-Can become severe + life threatening
-Complications include a “thyroid storm”
Clinical symptoms of hyperthyroidism/graves disease in children?
-Accelerated growth spurts
-Advanced bone age
-Emotional lability (mood swings)
-Hyperactivity
-Difficulty concentrating
-Occasionally failure to thrive
SF of hyperthyroidism/graves disease?
-Normal or enlarged thyroid
-Heterogeneous when enlarged
-Hypervascularity (aka thyroid inferno)
-Spectral doppler shows peak velocities exceeding 70 cm/sec
-Isthmus >1cm indicates diffuse enlargement
What is thyroiditis?
Term that includes multiple different types of disorders that involve some form of thyroid gland inflammation
What is the m/c presentation of thyroiditis?
Hypothyroidism (then thyrotoxicosis)
Acute vs acute suppurative symptoms of thyroiditis?
Acute:
-low grade fever
-sore neck
Acute suppurative (pus forming):
-bacterial + rare
-m/c in peds
-may see an abscess on u/s
Other names for subacute thyroiditis?
-De Quervain disease
-Granulomatous thyroiditis
Who m/c gets subacute thyroiditis?
-Female aged 30-50
-Possibly related to a viral cause
Clinical presentation of subacute thyroiditis?
-History of recent viral infection
-Neck pain (can radiate to upper jaw, throat or ears) which is associated with symptoms of inflammation like fever, tenderness, fatigue, anorexia, etc.
-Unilateral or bilateral enlargement of gland (usually temporary + resolves in 2-6 weeks)
-Spontaneous recovery of thyroid function in 6-8 weeks
-Good recovery (may have some residual fibrosis)
SF of acute or subacute thyroiditis?
-Enlargement
-Hypoechoic
-Normal or decreased vascularity
-Nodularity
What is goiters?
Enlargement of thyroid gland (m/c in women)
SF of goiters?
-Variable sizes (can get huge, especially in multi-nodular goiters)
-Isthmus >1cm (diffuse enlargement)
-Toxic or non-toxic
-Simple or multinodular
Symptoms of goiters?
Symptoms present when thyroid becomes enlarged + causes compression on the adjacent anatomy
-Dysphagia (from compression on esophagus)
-Inspiratory stridor (high pitched sound)
-Venous congestion (pressure on adjacent neck veins)
-Hoarseness (compression on laryngeal nerve)
Explain endemic non-toxic goiters?
Endemic: disease that is constantly present in a certain geographic area or in a certain group of people
-Due to deficiency in food, water + soil
-Hypothyroid causes a decrease in iodine + T3/T4, with an increase in TSH
Explain sporadic non-toxic goiters?
-These occur spontaneously in euthyroid pt’s in iodine sufficient areas
-M/c occurs b/w 35-60 years old
-Cause is unknown
Do non-toxic goiters cause the thyroid to have normal or abnormal function?
Normal, typically euthyroid
Explain toxic goiters?
-M/c multinodular
-Can cause hyperthyroidism / thyrotoxicosis / graves disease
(toxic meaning it produces T3 + T4)
What are multinodular goiters?
-Appears multi-lobulated + asymmetric enlargement of the thyroid
-Can involve 1 or both lobes + can extend below the clavicle/sternum (aka plunging goiter)
-Can be toxic or non-toxic
SF of multinodular goiters?
-Heterogeneous
-Lobulated + multinodular
-Possible calcifications
(must look for other discrete nodules within the goiter, as neoplasms + cancers can exist within a goiter too)
What causes thyroid disease in pregnancy?
Hormonal + physiological changes
What is 1 common presentation of thyroid disease in pregnancy?
Increase in thyroid size (due to reduction in plasma iodine), returns to normal size post-partum
What is the m/c condition after abortion, miscarriage or delivery?
Postpartum thyroiditis (PPT)
Classic presentation of PPT?
Thyrotoxicosis followed by hypothyroidism
SF of PPT?
-Decreased echogenicity
-Diffuse enlargement of thyroid
(must do bloodwork to determine PPT b/c the sono appearance is very non-specific)
15-25% of solitary thyroid nodules are what?
Cystic or mostly cystic (due to hemorrhage or degeneration)
Treatment of thyroid cysts?
Benign (only if symptomatic):
-Percutaneous ethanol injection
Malignant (rare):
-Surgery
What 2 types of thyroid cysts are there?
-Simple
-Complex (colloid + hemorrhagic cysts)
SF of simple thyroid cysts?
-Circular/oval
-Distinct margins
-No internal echoes
-Posterior enhancement
What are colloid cysts?
-Very common
-Irregularly enlarged follicles containing abundant colloid
-Can have calcifications
-Can have multiple echogenic foci (colloid crystals) with comet tail artifact (not microcalcifications)
What are hemorrhagic cysts?
-May contain blood + debris
-May have complex internal echoes, septations + debris
What are thyroid nodules?
-Term for a variety of different lesions (benign, malignant, etc.)
-Very common to have
-M/c in women
-Increased frequency with age + with decreased iodine intake
Differentiate b/w hot vs cold nodules?
Hot:
-Hyper functioning
-Area of dense collection of activity on nuclear med image
-Only 5-10% of nodules are hot (implies benignity)
Cold (m/c):
-Non functioning
-Area of decreased/absent activity on nuclear med image
-Majority of nodules are cold (10-15% are malignant)
Are hot or cold nodules m/c?
Cold (non-functioning)
The differentiation b/w hot + cold nodules is based on what?
Tc-99m (technetium-99m) nuclear medicine scintigraphy examination, this tracts how much iodine is absorbed into the nodules
What is the m/c cause of the majority of nodular diseases?
Hyperplasia
What causes hyperplasia?
-Iodine deficiency or under utilization
-If thyroid increases in size, can develop into a goiter
-M/c in females aged 35-50
SF of hyperplasia?
Variable:
-M/c isoechoic
-Echogenic (as thyroid increases in size)
-Peripheral halo
-Cystic degeneration (common)
-Perinodular vascularity
What is a thyroid adenoma?
Benign, neoplastic, slow growing nodule
(all adenomas are nodules + they make up 5-10% of nodules)
SF of thyroid adenomas?
M/c solitary, well-circumscribed + oval/circular!!
-Fibrous capsule
-Can be cystic, complex, solid, etc.
-Rim calcifications
-Halo (hypoechoic rim surrounding nodule, can be complete or incomplete)
-Spoke + wheel CD appearance
Are adenomas m/c in males or females?
7x more likely in females, aged 50-60
Most adenomas are derived from what subtype?
Follicular cells
Are most adenomas functioning or non-functioning?
Non-functioning
Rarely adenomas will produce what?
Thyroid hormones + cause hyperthyroidism (aka a toxic adenoma / hot nodule)
Follicular adenomas is indistinguishable from what other pathology?
Follicular carcinoma (can’t be distinguished on u/s or with an FNA)
What are the 2 m/c types of thyroid cancer?
1: papillary carcinoma
2: follicular carcinoma
(only 5-15% of nodules are malignant)
Incidence of thyroid carcinoma is m/c in what pt’s?
Pt’s with previous radiation exposure, but must have an FNA/biopsy done to confirm malignancy
SF of thyroid carcinomas?
-M/c solid + hypoechoic
-M/c feature specific to malignancy is microcalcifications (<2mm + appears as hyperechoic foci w/o shadowing)
-Taller than wide
-Tumor invasion or lymph node metastasis is very suspicious for thyroid malignancy
(hyperechoic = benign, hypoechoic = malignancy)
Differentiate the SFs b/w low + high thyroid risk of cancer?
Low:
-hyperechoic or isoechoic
-cystic
-large calcifications
-perinodular (peripheral) hypervascularity or avascular nodule
High:
-hypoechoic
-solid
-microcalcifications
-intrinsic (center) hypervascularity
-ill defined margins + shape is tall > wide
-local invasion + lymphadenopathy
(refer to table 15-4 in slides for full list)
Explain papillary cancer?
-M/c type of thyroid cancer
-Least aggressive + great prognosis/survival rate
-Spreads via the lymphatics
Who m/c gets papillary cancer?
Females aged 20-50
(but is more aggressive in men)
Clinical presentation of papillary cancer?
-Painless palpable lump
-Palpable nodule with enlarged cervical lymph nodes
-Enlarged cervical lymph nodes w/o palpable thyroid nodule
(must check for enlarged lymph nodes)
How can we diagnose + treat papillary cancer?
Diagnosis: with an FNA biopsy, as it is most accurate
Treatment: total/partial thyroidectomy or radical neck dissection, usually followed by suppressive therapy
SF of papillary cancer?
-Hypoechoic
-Microcalcifications
-Hypervascularity
-Punctate microcalcifications can appear in the affected lymph nodes if metastasis is present
Explain follicular cancer?
-2nd m/c
-M/c in females aged 40-50, with an increased incidence in areas of dietary iodine deficiency
-Is spread via the blood (hematological spread)
-Rarely spreads to neck nodes
Clinical presentation of follicular cancer?
-Slow growing + painless nodule
-Mets to bone, lungs or liver is seen
What is the diagnosis + treatment of follicular cancer?
Diagnosis: only made histologically (FNA is not effective)
Treatment: lobectomy or thyroidectomy, along with radioactive iodine treatment with widely invasive tumors
SF of follicular cancer?
Similar to follicular adenomas:
-irregular margins
-thick irregular halo
-chaotic vascularity
(rarely has specific features of malignancy)
List the types of thyroid cancers from most to least common?
-Papillary
-Follicular
-Medullary
-Anaplastic
-Hurthle cell
-Lymphoma
Explain medullary carcinoma?
-Is derived from parafollicular cells (aka c-cells) which secrete calcitonin
-Increases serum calcitonin
-M/c in females
Medullary carcinoma is associated with what syndrome?
MEN syndrome
Which type of thyroid cancer is aggressive + does not respond to chemo or radiation therapy?
Medullary cancer
Clinical presentation of medullary cancer?
-Mass in neck
-Other symptoms related to endocrine secretion (including carcinoid syndrome (serotonin) + cushing syndrome)
SF of medullary cancer?
Similar to papillary cancer:
-note that local invasion + mets to cervical lymph nodes is more common with medullary cancer
Explain anaplastic cancer?
-M/c in females over 60, with an increased incidence in endemic goiter areas
-Most aggressive thyroid cancer with a poor prognosis
-Invades nearby vasculature + muscles, widespread mets
-No effective treatments
Which form of thyroid cancer is the most aggressive with a poor prognosis?
Anaplastic cancer (no effective treatments, pt’s often only last about 5 years)
Clinical presentation of anaplastic cancer?
Rapidly enlarging neck mass with symptoms relating to the destruction of local structures
(such as dyspnea, dysphagia, hoarseness, cough)
SF of anaplastic cancer?
-Large, solid, hypoechoic mass with encasing or invading blood vessels
-Possibly invasion of other nearby structures as well
-Hard to assess due to size (CT or MRI is better)
Explain hurthle cell cancer?
-Has thyroglobulin producing cells
-Classified as either a benign or malignant hurthel cell adenoma based on histology
-Is aggressive
-M/c in males with advanced age
Diagnosis + treatment of hurthle cell cancer?
Diagnosis: histology (FNA not effective)
Treatment: total thyroidectomy
(clinical presentation + SF are variable)
Thyroid cancers are generally m/c in males or females?
Females, hurthle cell cancer is the only one m/c in males
Clinical presentation of thyroid lymphoma?
-M/c arise from chronic thyroiditis (hashimoto)
-Rapidly growing mass
-Symptoms of airway obstruction (dyspnea, dysphagia)
Diagnosis + treatment of lymphoma?
Diagnosis:
-surgery often done to diagnose it
-accuracy of FNA biopsy in diagnosing thyroid lymphoma is being researched
Treatment:
-radiation therapy + chemo
Which 2 thyroid cancers have no treatment?
-Medullary
-Anaplastic
SF of lymphoma?
-M/c large, solid, hypoechoic mass
-Infiltration of thyroid parenchyma + encasement of neck vessels (CCA, IJV)
-Cystic necrosis
-Doppler will be hypovascular or show chaotic blood vessel distribution
Is it common for cancer to metastasize to they thyroid?
-No! Very uncommon
-Occurs in late disease progression to another primary cancer
Thyroid mets is m/c spread by blood or lymphatics?
Blood
M/c mets to thyroid are from what?
Melanoma, breast, lung, RCC
SF of thyroid mets?
-Non specific
-M/c hypoechoic
T/F: Heat intolerance is a symptom of hypothyroidism?
False, is a symptom of hyperthyroidism
(cold = hypothyroidism, hot = hyperthyroidism)
What is the m/c cause of primary hypothyroidism?
Hashimotos or iodine insufficiency worldwide
What is the m/c form of thyroid cancer?
Papillary
Thyroid inferno is a common sonographic feature in which condition?
Graves disease / hyperthyroidism
Serum calcitonin can be used as a tumor marker for which type of thyroid carcinoma?
Medullary (from the c-cells, which secrete calcitonin)
Based on Tc-99m, hot nodules are usually ____?
Benign
