Thyroid, Parathyroid, and Neck Tanya Nolan. Thyroid Gland Anatomy

Thyroid, Parathyroid, Thyroid, Parathyroid, and Neckand Neck

Tanya NolanTanya Nolan

Thyroid Gland AnatomyThyroid Gland Anatomy

Anatomic VariationsAnatomic Variations Thyroglossal Duct Thyroglossal Duct

CystCyst Thyroglossal duct fails to Thyroglossal duct fails to

involute completelyinvolute completely

AthyrosisAthyrosis Absence of Thyroid Absence of Thyroid

glandgland

Pyramidal LobePyramidal Lobe Absence of Absence of

IsthmusIsthmus Ectopic GlandEctopic Gland

Neck AnatomyNeck Anatomy

Normal AnatomyNormal Anatomy

Normal AnatomyNormal Anatomy

Function and PhysiologyFunction and Physiology Maintains body metabolism, growth, and Maintains body metabolism, growth, and

development development synthesis, storage, & secretion of thyroid synthesis, storage, & secretion of thyroid

hormoneshormones1.1. Thyroid gland traps iodine (used for synthesis) Thyroid gland traps iodine (used for synthesis)

2.2. Produces triiodothyronine (T3) & thyroxine (T4) Produces triiodothyronine (T3) & thyroxine (T4)

3.3. Thyroid hormone released into bloodstream via action Thyroid hormone released into bloodstream via action of thyrotopin (TSH) produced by the pituitary glandof thyrotopin (TSH) produced by the pituitary gland

Thyroxine (T4)Thyroxine (T4) Iodine + Tyrosine (amino acid)Iodine + Tyrosine (amino acid) Combines with protein thyroglobulin & stored.Combines with protein thyroglobulin & stored.

Increases carbohydrate burnIncreases carbohydrate burn Breaks down proteins for energyBreaks down proteins for energy Regulates fat metabolism Regulates fat metabolism Accelerates body growth (especially nervous tissue)Accelerates body growth (especially nervous tissue) Increases nervous system reactivityIncreases nervous system reactivity

CalcitoninCalcitonin Produced by parafollicular cells (C cells of Produced by parafollicular cells (C cells of

thyroid gland) in response to high calcium thyroid gland) in response to high calcium levelslevels

DecreasesDecreases the concentration of calcium in the concentration of calcium in the blood by inhibiting bone break down (less the blood by inhibiting bone break down (less Ca absorbed)Ca absorbed)

What happens when blood What happens when blood

Calcium concentrations are Calcium concentrations are

HIGH?HIGH?

Thyroid Stimulating Thyroid Stimulating Hormone (TSH)Hormone (TSH)

Produced by the Produced by the anterior anterior pituitary glandpituitary gland

Regulated by the Regulated by the thyrotropin-releasing thyrotropin-releasing factor (TRF) produced factor (TRF) produced by the by the hypothalmushypothalmus

TRF regulated by the TRF regulated by the basal metabolic rate.basal metabolic rate.

Feedback SystemFeedback System>>Decreased Metabolic Rate Decreased Metabolic Rate

LOW OR HIGH Concentration of Thyroid LOW OR HIGH Concentration of Thyroid Hormone (Thyroxine)?Hormone (Thyroxine)?

>Hypothalmus releases Thyrotropin-Releasing Factor(TRF)>Hypothalmus releases Thyrotropin-Releasing Factor(TRF)

Thyroid Stimulating Hormone (TSH) Thyroid Stimulating Hormone (TSH) Released by Released by __________?__________?

>Increase in Thyroid Hormone >Increase in Thyroid Hormone

Blood Concentration Normal Blood Concentration Normal

Basal Metabolic Rate NormalBasal Metabolic Rate Normal

>TRF inhibited >TRF inhibited

Lab TestsLab Tests Nuclear MedicineNuclear Medicine

Most accurate for T3 & T4 levels. Most accurate for T3 & T4 levels. Radioactive iodine injected into Radioactive iodine injected into

the bloodstream & % of uptake the bloodstream & % of uptake monitored by gamma camera. monitored by gamma camera.

HOT NODULEHOT NODULE: A : A

hyperfunctioning nodule or hyperfunctioning nodule or COLD NODULECOLD NODULE: hypoactive : hypoactive

nodule.nodule.

What type of nodule is What type of nodule is MOSTMOST suspicious of suspicious of carcinoma? carcinoma?

Lab TestsLab Tests Triiodothyronine (T3)Triiodothyronine (T3)

Normal RIA 80-160 ng/dl; RU: 25-35% relative uptakeNormal RIA 80-160 ng/dl; RU: 25-35% relative uptake

Serum Thyroxine (T4)Serum Thyroxine (T4) Normal Serum T4: 5-11 mg/dl. Normal Serum T4: 5-11 mg/dl. Elevated levelsElevated levels seen in hyperthyroidism and acute thyroiditis. seen in hyperthyroidism and acute thyroiditis. Low levelsLow levels are seen in hypothyroidism, myxedema, cretinism, chronic are seen in hypothyroidism, myxedema, cretinism, chronic

thyroiditis, and occasionally in subacute thyroiditis.thyroiditis, and occasionally in subacute thyroiditis.

Serum CalcitoninSerum Calcitonin Elevated levelsElevated levels of calcitonin are diagnostic of medullary carcinoma of of calcitonin are diagnostic of medullary carcinoma of

the thyroidthe thyroid

Serum Thyroid Stimulating HormoneSerum Thyroid Stimulating Hormone Normal Serum TSH < 5mU/mlNormal Serum TSH < 5mU/ml TSH level is indicative of thyroid reserve. It is the TSH level is indicative of thyroid reserve. It is the most accurate test most accurate test

for for primary primary hypothyroidismhypothyroidism

Indications for Indications for Sonographic Sonographic ExaminationExamination

Palpable enlargementPalpable enlargement Abnormal Thyroid Hormone Level(s)Abnormal Thyroid Hormone Level(s) Palpable mass in neck / thyroidPalpable mass in neck / thyroid Swelling of neckSwelling of neck Asymmetry of neckAsymmetry of neck Redness and/or tendernessRedness and/or tenderness

Sonographic TechniqueSonographic Technique EquipmentEquipment

High frequency (7.5-15 MHz or higher) linear High frequency (7.5-15 MHz or higher) linear TransducerTransducer

Patient PositionPatient Position Supine with neck extendedSupine with neck extended

ViewsViews Longitudinal and Transverse images of bilateral Longitudinal and Transverse images of bilateral

lobes & Transverse view of the isthmuslobes & Transverse view of the isthmus Demonstrate relational anatomyDemonstrate relational anatomy

Normal Normal ThyroidThyroid

Adult Thyroid

40-60 mm long

13-18 mm AP

Isthmus 4-6 mm AP

Newborn: 18-20 mm long; 8-9 mm AP

Age 1: 25 mm long; 12-15 mm AP

Nontoxic GoiterNontoxic Goiter Simple, Colloid, or MultinodularSimple, Colloid, or Multinodular

Enlargement of entire gland without Enlargement of entire gland without producing nodularity and without evidence of producing nodularity and without evidence of functional disturbance (euthyroid)functional disturbance (euthyroid)

CausesCauses Lack of IodineLack of Iodine

Compensatory increase of TSH = follicular cell Compensatory increase of TSH = follicular cell hypertrophyhypertrophy

Sporatic GoiterSporatic Goiter Diffuse, Uninodular, or multinodularDiffuse, Uninodular, or multinodular Ingestion of Substances, hereditary enzyme Ingestion of Substances, hereditary enzyme

defectsdefects Simple Goiters may evolve = Simple Goiters may evolve =

Multinodular GoitersMultinodular Goiters Calcification, Degeneration, Fibrosis, Calcification, Degeneration, Fibrosis,

and Hemorrhageand Hemorrhage

Thyrotoxicosis / Thyrotoxicosis / HyperthyroidismHyperthyroidism

Over secretion of thyroid hormonesOver secretion of thyroid hormones Clinical SignsClinical Signs

Dramatic increase in metabolic rateDramatic increase in metabolic rate Weight LossWeight Loss Increased appetiteIncreased appetite Nervous energyNervous energy TremorTremor Excessive sweatingExcessive sweating Heat intoleranceHeat intolerance Cardiac PalpitationsCardiac Palpitations Exopthalmos (protruding eyes)Exopthalmos (protruding eyes)

CausesCauses Abnormal hormone secretion (entire gland out of control)Abnormal hormone secretion (entire gland out of control) Localized neoplasm caused by overproduction of hormonesLocalized neoplasm caused by overproduction of hormones Grave’s diseaseGrave’s disease

Toxic Multinodular GoiterToxic Multinodular Goiter“Grave’s Disease”“Grave’s Disease”

Clinical SignsClinical Signs Women over 30Women over 30 HypermetabolismHypermetabolism ExopthalmosExopthalmos Cutaneous formations (periorbital and dorsum of feet)Cutaneous formations (periorbital and dorsum of feet)

CausesCauses Autoimmune Autoimmune hyperthyroidismhyperthyroidism

Sonographic FindingsSonographic Findings Diffuse enlargementDiffuse enlargement Hypoechoic without Hypoechoic without palpable nodulespalpable nodules Markedly increased Markedly increased vascularity vascularity (“thyroid (“thyroid inferno”)inferno”)

HypothyroidismHypothyroidism Lack of secretion of thyroid hormonesLack of secretion of thyroid hormones

Clinical SignsClinical Signs Myxedema (skin and tissue disorder)Myxedema (skin and tissue disorder) Weight gainWeight gain Hair lossHair loss Increased tissue around the eyesIncreased tissue around the eyes LethargyLethargy Intellectual and motor slowing Intellectual and motor slowing Cold IntoleranceCold Intolerance ConstipationConstipation Deep, husky voiceDeep, husky voice

Causes Causes Primary = Thyroid hormone failure Primary = Thyroid hormone failure Secondary = Diseases of the hypothalmus or pituitarySecondary = Diseases of the hypothalmus or pituitary

TreatmentTreatment Synthetic thyroid hormone can reverse the conditionSynthetic thyroid hormone can reverse the condition

ThyroiditisThyroiditis Most common cause of primary hypothyroidism in Most common cause of primary hypothyroidism in

iodine rich areas of the worldiodine rich areas of the world Inflammation of the thyroid causing swelling and Inflammation of the thyroid causing swelling and

tendernesstenderness May be associated with lymphomaMay be associated with lymphoma

CausesCauses InfectionInfection AutoimmuneAutoimmune

TypesTypes De QuervainsDe Quervains Hashimoto’sHashimoto’s

De Quervain’sDe Quervain’s Clinical SignsClinical Signs

Usually viral Usually viral Diffuse enlargementDiffuse enlargement Tenderness / mild to severe painTenderness / mild to severe pain Transient hyperthyroidismTransient hyperthyroidism Gradual or fairly abrupt onsetGradual or fairly abrupt onset

Hashimoto’sHashimoto’s Increased risk for malignant diseaseIncreased risk for malignant disease Clinical SignsClinical Signs

Most common form of thyroiditisMost common form of thyroiditis Autoimmune – chronic inflammationAutoimmune – chronic inflammation Diffuse enlargementDiffuse enlargement possibly asymmetricpossibly asymmetric PainlessPainless may develop mild pain over timemay develop mild pain over time Eventual hypothyroidismEventual hypothyroidism Young – middle aged femalesYoung – middle aged females

Sonographic Findings:

1. Increased Vascularity with Color Doppler

2. Texture is course and homogenous with multiple ill-defined hypoechoic areas separated by thick fibrous strands

3. Over time, the gland becomes fibrotic, ill-defined, and heterogeneous

Thyroid Disease and Pregnancy

• 2nd most common endocrinopathy that affects women of reproductive age.

Increase TBG (Thyroid Binding Globulin)Decreased TSH between weeks 8-14Reduced plasma iodine

• Increased gland size in 13% women

• Post Partum Thyroiditis

Benign MassesBenign MassesCysts and Cystic NodulesCysts and Cystic Nodules

Sonographic AppearanceSonographic Appearance Purely anechoic areas (serous / colloid fluid), well-Purely anechoic areas (serous / colloid fluid), well-

defined walls, & distal enhancement.defined walls, & distal enhancement. Fluid levels (hemorrhage)Fluid levels (hemorrhage) FNA / Ethanol InjectionFNA / Ethanol Injection

Degenerative Colloid Cysts

Benign MassesBenign MassesAdenomasAdenomas

Most common solid thyroid massMost common solid thyroid mass Encapsulated nodule Encapsulated nodule

compression of adjacent tissuescompression of adjacent tissues fibrous encapsulationfibrous encapsulation

Clinical FeaturesClinical Features Most patients euthyroid or hyperthyroidMost patients euthyroid or hyperthyroid Slow growing – must be 0.5 – 1 cm to be palpatedSlow growing – must be 0.5 – 1 cm to be palpated

Sonographic AppearanceSonographic Appearance Variable sonographic appearanceVariable sonographic appearance Follicular carcinoma is indistinguishable from an Follicular carcinoma is indistinguishable from an

adenomaadenoma

AdenomasAdenomas Well circumscribed; circular Well circumscribed; circular

shapedshaped Peripheral haloPeripheral halo (edema of (edema of

compressed tissue)compressed tissue) Increased Color Flow Increased Color Flow Cystic DegenerationCystic Degeneration Rim CalcificationRim Calcification Homogeneous with variable Homogeneous with variable

size; Hyperechoicsize; Hyperechoic Slow growing unless Slow growing unless

hemorrhage occurs (sudden hemorrhage occurs (sudden painful enlargement)painful enlargement)

MalignaMalignant nt

MassesMasses

Carcinoma of the thyroid is rare!Carcinoma of the thyroid is rare! Risk of malignancy decreases with Risk of malignancy decreases with multiplemultiple nodules nodules A A solitary thyroid solitary thyroid nodule in the presence of nodule in the presence of cervical adenopathycervical adenopathy

on the same side suggests on the same side suggests malignancymalignancy Clinical FindingsClinical Findings

Asymptomatic noduleAsymptomatic nodule HoarsenessHoarseness History of exposure to low dose ionizing radiationHistory of exposure to low dose ionizing radiation Solitary fixed, rapidly enlarging nodule in patient under 14 years or over Solitary fixed, rapidly enlarging nodule in patient under 14 years or over

65 years of age65 years of age

Papillary CarcinomaPapillary Carcinoma Most common thyroid malignancyMost common thyroid malignancy

Sonographic FindingsSonographic Findings HypoechoicHypoechoic MicrocalcificationsMicrocalcifications HypervascularityHypervascularity Possible cervicalPossible cervical

lymph node metastasislymph node metastasis

Medullary Carcinoma Medullary Carcinoma C - CellsC - Cells

Clinical FindingsClinical Findings Hard, bulky massHard, bulky mass Abnormal serum calcitonin Abnormal serum calcitonin

levelslevels

Sonographic FindingsSonographic Findings Solid mass Solid mass CalcificationsCalcifications LymphadenopathyLymphadenopathy

Metastasis Metastasis to Lymph to Lymph

NodesNodes

How does the appearance of a normal lymph node differ from an abnormal lymph node?

Normal

Anaplastic (Undifferentiated) Anaplastic (Undifferentiated) CarcinomaCarcinoma

Clinical signsClinical signs > 50 years of age> 50 years of age Hard, fixedHard, fixed Rapid growthRapid growth Pain, pressure, Pain, pressure,

tendernesstenderness Locally invasiveLocally invasive

Sonographic FindingsSonographic Findings Hypoechoic mass, Hypoechoic mass,

possibly irregularpossibly irregular Diffuse glandular Diffuse glandular

involvementinvolvement Invasion of Invasion of

surroundingssurroundings

Features of Benign/Malignant Features of Benign/Malignant NodulesNodules

Feature Benign Malignant

Internal ContentsPurely CysticCystic with Thin SeptaMixed Solid and CysticComet Tail Artifact

 ++++++++++++++

 +++++

EchogenicityHyperechoicIsoechoicHypoechoic

 ++++++++++

 ++++++

HaloThin HaloThick Incomplete Halo

 +++++

 +++++

MarginWell DefinedPoorly Defined

 +++++

 +++++

CalcificationEggshellCourseMicrocalcifications

 +++++++++

 ++++++

Doppler Flow PatternPeripheralInternal

 +++++

 +++++

Parathyroid GlandParathyroid Gland 4 small masses on 4 small masses on posterior posterior

surface of the lateral lobessurface of the lateral lobes PhysiologyPhysiology

Monitors Monitors Calcium Calcium MetabolismMetabolism

Produces Parathyroid Produces Parathyroid HormoneHormoneSerum Calcium LowSerum Calcium LowPTH SecretedPTH Secreted

Releases calcium from Releases calcium from bones bones

Changes intestinal tract Changes intestinal tract absorptionabsorption

Parathyroid GlandParathyroid Gland Texture similar to overlying Texture similar to overlying

thyroid thyroid (size <4 mm glands are usually (size <4 mm glands are usually not seen)not seen) Be careful to evaluate in sagittal Be careful to evaluate in sagittal

and transverse views so not to and transverse views so not to mistake a muscle for mistake a muscle for parathyroid!parathyroid!

Enlarged glands have Enlarged glands have decreased echo texture and decreased echo texture and appear elongated masses appear elongated masses between the posterior longus between the posterior longus coli and the anterior thyroid coli and the anterior thyroid lobe.lobe.

Parathyroid PathologyParathyroid Pathology Primary HyperparathyroidismPrimary Hyperparathyroidism

Increased function of parathyroid glandIncreased function of parathyroid gland

AdenomasAdenomas Most common cause of primary hyperparathyroidismMost common cause of primary hyperparathyroidism Benign and usually less than 3 cmBenign and usually less than 3 cm

CarcinomaCarcinoma Most small, irregular, & firm; may adhere to surrounding Most small, irregular, & firm; may adhere to surrounding

structures. structures.

Secondary HyperparathyroidismSecondary Hyperparathyroidism Chronic hypocalcemia Chronic hypocalcemia

renal failure, vitamin D deficiency, or malabsorption syndromesrenal failure, vitamin D deficiency, or malabsorption syndromes PTH secretion to compensate for renal insufficiency and PTH secretion to compensate for renal insufficiency and

intestinal malabsorption.intestinal malabsorption.

Neck MassesNeck MassesThyroglassal Duct CystThyroglassal Duct Cyst

Congenital anomaly Congenital anomaly Midline & anterior to Midline & anterior to

trachea trachea Remnant of tubular dev’t Remnant of tubular dev’t

of thyroid gland persisting of thyroid gland persisting between the base of the between the base of the tongue and the hyoid tongue and the hyoid bonebone

Clinical SignsClinical Signs Palpable midline massPalpable midline mass Pain associated with Pain associated with

hemorrhage or infectionhemorrhage or infection Sonographic FindingsSonographic Findings

Cystic mass in the midline Cystic mass in the midline anterior to the tracheaanterior to the trachea

Internal echoes caused by Internal echoes caused by hemorrhage or infectionhemorrhage or infection

Oval, sphericalOval, spherical

Brachial Cleft Brachial Cleft CystCyst

Anterior to CCAAnterior to CCA Along the border of the Along the border of the

sternocleidomastoid sternocleidomastoid musclemuscle

Definite separation from Definite separation from the thyroid glandthe thyroid gland

Cystic HygromaCystic Hygroma

Congenital lymphatic Congenital lymphatic malformation of malformation of posterolateral neckposterolateral neck

Webbed neckWebbed neck

Sonographic FindingsSonographic Findings Thin walled, cystic Thin walled, cystic

multiloculated massmultiloculated mass

Thyroid ScanThyroid Scan