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THYROID GLAND - COMPLETE EXAM NOTES

Sources: Sabiston Textbook of Surgery, Schwartz's Principles of Surgery 11e, Scott-Brown's ENT Surgery, ATA 2015/2025 Guidelines

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SECTION 1: EMBRYOLOGY

Origin

• The thyroid gland arises from two anlages - median and lateral - that follow separate embryologic paths and fuse to form one gland.
• Median thyroid anlage: Thickening of endodermal epithelium of the foregut in the floor of the pharynx (adjacent to myocardial cells); becomes a bilobed diverticulum connected to the tongue via the thyroglossal duct.
• The thyroglossal duct becomes solid in the 5th week, then fragments and disappears.
  • Superiorly: leaves the foramen cecum at the base of the tongue
  • Inferiorly: leaves the pyramidal lobe (when present)
• Thyroid descends to its final position anterior to the trachea by the 7th week
• Follicles form and produce thyroid hormone by the 10th week of gestation

Lateral thyroid anlage

• Arises from pharyngeal endoderm, fuses with median anlage in the 5th week
• Contains cells derived in part from the neural crest (gives rise to C cells / parafollicular cells that produce calcitonin)

Exam Points on Embryology

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SECTION 2: ANATOMY

Gross Anatomy

• Adult: brown, firm gland; bilobed connected by isthmus
• Lies posterior to the strap muscles and anterior to the trachea
• Weight: 20-30 g (normal)
• Each lobe: 4 cm long, 2 cm wide
• Pyramidal lobe: present in ~50% - extends from isthmus upward (left of midline)
• Tubercle of Zuckerkandl: posterolateral extension of the thyroid lobe at the level of the cricoid cartilage; important landmark for identifying the RLN

Blood Supply

Venous Drainage

• Superior thyroid vein - drains into internal jugular vein (with superior thyroid artery)
• Middle thyroid vein - least consistent; drains into internal jugular vein
• Inferior thyroid veins - form a plexus draining into the brachiocephalic veins

Nerves (MOST IMPORTANT FOR SURGERY)

Recurrent Laryngeal Nerve (RLN)

• Left RLN: arises from vagus at the aortic arch, loops around ligamentum arteriosum, ascends in the tracheoesophageal groove
• Right RLN: arises from vagus at right subclavian artery, loops posteriorly, more oblique course
• Non-recurrent right RLN: occurs in 0.5-1%, associated with vascular anomaly (aberrant right subclavian artery)
• The RLN may branch before entering the larynx (25% pass through the ligament of Berry)
• Enters larynx posterior to the cricothyroid muscle
• Innervates: all intrinsic laryngeal muscles except cricothyroid
• Injury: unilateral = hoarseness; bilateral = stridor/airway compromise

External Branch of the Superior Laryngeal Nerve (EBSLN)

• Branch of the superior laryngeal nerve (from vagus)
• Innervates the cricothyroid muscle (voice pitch/tension)
• Runs close to superior pole vessels - at risk during superior pole dissection
• Injury: vocal fatigue, loss of high-pitched voice, decreased voice projection
• Estimated injury rate: 2.5-28% (often subclinical)
• Cernea classification of EBSLN position: Type I (>1 cm above superior pole vessels, safest), Type IIA (<1 cm), Type IIB (below vessels, highest risk)

Parathyroid Glands

• Typically 4 glands; occasionally 3 or 5
• Superior parathyroids: dorsal to the plane of the RLN (posterior to intersection of inferior thyroid artery and RLN) - more constant position
• Inferior parathyroids: ventral to the plane of the RLN - more variable position
• Blood supply from inferior thyroid artery (both superior and inferior glands)
• Extremely delicate blood supply; can be devascularized even without direct injury

Fascia

• True capsule: inner fibrous capsule of the thyroid
• False capsule (surgical capsule): condensation of the pretracheal fascia
• Ligament of Berry (posterior suspensory ligament): connects the thyroid to the trachea; important because RLN branches may traverse it in 25% of individuals

Lymphatics

• Extensive lymphatic drainage to paratracheal, prelaryngeal (Delphian), mediastinal, and lateral cervical nodes
• Delphian node: prelaryngeal lymph node; if positive on palpation, suggests thyroid cancer or laryngeal cancer

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SECTION 3: HISTOLOGY & PHYSIOLOGY

Histology

• Follicular cells (thyrocytes): produce T3/T4; arranged in spherical follicles surrounding colloid
• Colloid: central store of thyroglobulin (the iodinated precursor to thyroid hormone)
• Parafollicular C cells: produce calcitonin; located in the parafollicular spaces; derived from lateral thyroid anlage/neural crest

Normal Thyroid Physiology

• TSH (from anterior pituitary) stimulates follicular cells to transport thyroid hormones from colloid into bloodstream
• T4 (thyroxine) is the major secretory product; T3 is more potent

• 99% of circulating thyroid hormones are protein-bound (albumin, TBG, TTR); <1% is free (biologically active)

• Target organs (brain, liver, gut, skeletal muscle) convert T4 → T3 via deiodinase system
• Daily iodine requirement: 0.1 mg/day (entirely from diet)
• Actions of thyroid hormone: bind mitochondrial receptors → ↑ATP, O2 consumption, glucose oxidation (calorigenic) → drives basal metabolic rate

HPT Axis

Hypothalamus → TRH → Anterior Pituitary → TSH → Thyroid → T3/T4 → Negative feedback to hypothalamus and pituitary

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SECTION 4: THYROID BIOMARKERS / INVESTIGATIONS

Imaging

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SECTION 5: THYROID NODULE

Clinical Features That Raise Cancer Risk

• Hard, fixed nodule
• Rapid growth
• History of head/neck radiation
• Family history of thyroid cancer or MEN
• Age <20 or >70
• Male sex
• Dysphonia, dysphagia, dyspnea (compressive symptoms)
• Cervical lymphadenopathy

Workup Algorithm

1. TSH first - if low, do scintigraphy (hot = likely benign, no FNA needed)
2. Ultrasound - characterize nodule
3. FNA biopsy - if indicated by ultrasound risk features

ATA/ACR TIRADS Ultrasound Features of Concern (High-Risk Features)

• Hypoechoic (compared to strap muscles)
• Irregular margins
• Microcalcifications
• Taller-than-wide orientation
• Extra-thyroidal extension

FNA Bethesda Classification

Molecular Testing (for Indeterminate FNA - Bethesda III/IV)

• Afirma GSC (Gene Expression Classifier): "rule-out" test; high NPV; sensitivity 91%, specificity 68%
• ThyroSeq v3: next-gen sequencing; sensitivity 94%, specificity 82%, NPV 97%; detects BRAF, RAS, RET/PTC, PAX8/PPAR-gamma fusions

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SECTION 6: THYROID DISEASES

Hypothyroidism

Hashimoto Thyroiditis (Chronic Autoimmune Thyroiditis)

• Most common cause of hypothyroidism in iodine-sufficient countries
• Autoimmune: TPO antibodies + anti-Tg antibodies; lymphocytic infiltration with germinal center formation
• Cytology: oncocytic (Hurthle cell) change, lymphocytic infiltration, minimal colloid
• Complications: primary thyroid lymphoma (rare; 2/million/year; associated with Hashimoto's)
• Treatment: Levothyroxine replacement

Subacute Thyroiditis (de Quervain / Granulomatous Thyroiditis)

• Female > male (2:1); fourth decade
• Often follows viral upper respiratory infection
• Clinical: painful, tender thyroid + fever + dysphagia + elevated ESR (diagnostic)
• Phase: hyperthyroidism → euthyroid → hypothyroidism → recovery (2-5 months)
• Cytology: multinucleated giant cell granulomas
• Treatment: NSAIDs; corticosteroids for severe cases; self-limited - surgery NOT indicated

Riedel Thyroiditis

• Rare; fibrous replacement of thyroid extending to surrounding tissues
• "Woody/iron-hard" thyroid; can mimic anaplastic cancer
• Associated with multifocal fibrosclerosis (orbital pseudotumor, retroperitoneal fibrosis, primary sclerosing cholangitis)
• Surgery for compressive symptoms only; steroids + tamoxifen for medical management

Postpartum Thyroiditis

• Occurs in up to 10% of females within 1-12 months postpartum
• Similar to Hashimoto's; associated with TPO antibodies
• Short-lived (2-4 months); 10-fold increased risk of developing Hashimoto's later

Hyperthyroidism

Graves Disease

• Most common cause of hyperthyroidism
• Autoimmune: TSI (thyroid-stimulating immunoglobulins) bind TSH receptor → hyperstimulation
• Triad: hyperthyroidism + diffuse goiter + exophthalmos (ophthalmopathy)
• Other features: pretibial myxedema (dermopathy), thyroid acropachy, onycholysis, clubbing
• Diagnosis: low TSH, high fT4/fT3, TSI/TRAb positive; diffuse uptake on scintigraphy
• Treatment options:
  1. Antithyroid drugs (methimazole preferred; PTU in 1st trimester pregnancy / thyroid storm)
  2. Radioiodine (RAI / I-131) - causes thyroid ablation; contraindicated in active ophthalmopathy, pregnancy
  3. Surgery (thyroidectomy) - indications: large goiter, coexistent malignancy, ophthalmopathy worsened by RAI, patient preference, pregnancy contraindications, failed medical therapy
  • Preoperative prep: achieve euthyroid state with antithyroid drugs; Lugol's solution (SSKI) 10 days before surgery (reduces vascularity and iodine uptake); beta-blockers

Toxic Multinodular Goiter (Plummer Disease)

• Second most common cause of hyperthyroidism
• Multiple autonomously functioning nodules; constitutively activating TSH receptor mutations
• Scintigraphy: heterogeneous uptake; multiple hot nodules with suppressed background
• Treatment: RAI or total thyroidectomy (antithyroid drugs not curative)

Toxic Adenoma

• Single autonomously functioning nodule; TSH receptor mutation
• Scintigraphy: single hot nodule with suppressed background
• Treatment: RAI or lobectomy (lobectomy = near-universal cure)

Amiodarone-Induced Thyrotoxicosis (AIT)

• Amiodarone: 37% iodine by molecular weight; contains 100x daily iodine requirement
• Occurs in up to 6% of patients on amiodarone
• Type 1: Jod-Basedow - excess iodine → excess synthesis (preexisting thyroid disease)
• Type 2: Destructive thyroiditis - drug toxicity → release of preformed hormone (no prior thyroid disease)
• Treatment: methimazole + corticosteroids; total thyroidectomy if unresponsive (perioperative mortality 9-10% but delay = higher mortality)

Thyroid Storm

• Life-threatening thyrotoxicosis (mortality up to 50%)
• Triggers: surgery, infection, postpartum, iodine contrast, withdrawal of antithyroid drugs
• Features: fever/hyperpyrexia, tachyarrhythmia, CNS disturbance, vomiting, diarrhea, multi-organ failure
• Treatment (Burch-Wartofsky criteria):
  1. PTU 300 mg q6h NG (blocks T4→T3 conversion)
  2. Potassium iodide 60 mg q6h NG - start 6 hours AFTER PTU (inhibits thyroid hormone release)
  3. Propranolol 160-180 mg divided or IV infusion (blocks adrenergic manifestations)
  4. Prednisolone 60 mg OD (stops T4→T3 conversion)
  5. Cooling, IV fluids, antibiotics, respiratory support in ICU/ITU
  6. Plasmapheresis for refractory cases

Myxedema Coma

• Life-threatening hypothyroidism
• Triggers: elderly + withdrawal of thyroxine + severe illness + immobility/cold exposure
• Features: coma, hypothermia, bradycardia, hyponatremia, hypoglycemia, hypotension
• Treatment:
  1. T4 300-500 mcg via NG tube, then 50-100 mcg daily
  2. If no improvement: T3 10 mcg IV 8-hourly (or 25 mcg oral)
  3. Hydrocortisone 50-100 mg q6-8h (unless hypocortisolism excluded)
  4. Slow rewarming (0.5°C/hour), HDU/ITU care

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SECTION 7: THYROID CANCER

Classification

Papillary Thyroid Cancer

• Most common thyroid malignancy
• Pathognomonic features: "Orphan Annie eye" nuclei (empty-appearing, pale chromatin), intranuclear pseudo-inclusions, intranuclear grooves, psammoma bodies
• Risk factors: prior radiation exposure (head/neck radiation; Chernobyl), family history, female sex
• BRAF V600E mutation: most common in PTC; associated with more aggressive disease
• RET/PTC rearrangements: especially in radiation-induced PTC
• Spreads primarily via lymphatics → cervical lymph nodes
• Usually cold nodule on scintigraphy
• Staging: MACIS score (Metastasis, Age, Completeness of resection, Invasion, Size)
• Prognosis: excellent - 20-year survival >95% in low-risk patients

Follicular Thyroid Cancer

• FNA cannot distinguish follicular adenoma from FTC (both = Bethesda IV / "follicular neoplasm")
• Diagnosis requires histology showing capsular or vascular invasion on surgical specimen
• Spreads hematogenously (lung, bone, brain)
• PAX8/PPAR-gamma rearrangement, RAS mutations
• RAI-avid (unlike anaplastic/Hurthle cell)

Medullary Thyroid Cancer

• Arises from C cells (calcitonin-producing)
• Calcitonin: diagnostic and surveillance marker
• CEA: also elevated
• 75% sporadic; 25% hereditary (RET proto-oncogene mutations)
  • MEN2A: MTC + pheochromocytoma + primary hyperparathyroidism (RET codon 634)
  • MEN2B: MTC + pheochromocytoma + marfanoid habitus + mucosal neuromas (RET codon 918; most aggressive)
  • FMTC: familial MTC only
• RET mutation testing: all MTC patients should undergo genetic testing; positive family members need prophylactic thyroidectomy
• Prophylactic thyroidectomy timing (ATA risk categories):
  • Highest risk (codon 918): within first 6 months of life
  • High risk (codon 634): by age 5
  • Moderate risk: by age 5-10 or when calcitonin becomes detectable

Anaplastic Thyroid Cancer

• Rapidly growing, invades local structures; extremely aggressive
• Often presents with airway compromise requiring urgent management
• No effective systemic therapy; surgery rarely curative
• Lenvatinib + pembrolizumab (immunotherapy): emerging treatment; BRAF V600E mutations → dabrafenib + trametinib

ATA Risk Stratification for DTC (2015/2025 Guidelines)

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SECTION 8: SURGICAL TECHNIQUE - THYROIDECTOMY

Nomenclature of Thyroidectomy

Indications for Thyroid Surgery

• Thyroid cancer (confirmed or suspicious FNA)
• Compressive symptoms from goiter (dysphagia, dyspnea, stridor)
• Substernal goiter
• Hyperthyroidism not responding to medical therapy / radioiodine
• Cosmesis / patient preference
• Graves disease (especially with ophthalmopathy, pregnancy, large goiter, young patients)
• FNA Bethesda IV/V/VI
• Amiodarone-induced thyrotoxicosis unresponsive to medical therapy

ATA 2015 Surgical Recommendations for DTC

• Lobectomy acceptable for: low-risk DTC <4 cm, no extrathyroidal extension, no clinical LN involvement, no distant metastases
• Total thyroidectomy indicated for: tumors >4 cm, high-risk features, extrathyroidal extension, positive nodes, bilateral disease, distant metastases, need for RAI ablation
• 2025 update: continues to support this risk-based approach; emphasizes shared decision-making

Preoperative Preparation

1. Biochemical thyroid function tests
2. Neck ultrasound (all patients)
3. For hyperthyroidism: achieve euthyroid state pre-operatively (antithyroid drugs ± β-blocker)
4. For Graves disease: Lugol's solution or SSKI within 10 days of surgery (reduces vascularity)
5. Preoperative voice assessment (history of voice changes → laryngoscopy)
6. Laryngoscopy: mandatory for known thyroid cancer, prior neck surgery, voice abnormalities
7. For MEN2A: check calcium to rule out concurrent hyperparathyroidism

Anesthesia and Positioning

• General endotracheal anesthesia (standard)
• Neuromonitoring ETT (NIM tube) with electrodes contacting vocal cords if IONM planned
• Position: supine, both arms tucked
• Back raised 20 degrees
• Neck extended with soft roll behind scapulae; head on foam/gel ring
• Muscle relaxants avoided if nerve monitoring is used

Operative Steps (Schwartz's / Sabiston Technique)

• Centrally placed transverse collar incision (Kocher's incision)
• Placed in a natural skin crease between sternal notch and cricoid cartilage
• Length: typically 4-5 cm (adjusted for gland size and patient habitus)
• Extended through the platysma

• Flaps raised superiorly to the thyroid cartilage
• Flaps raised inferiorly to the sternal notch
• Identify anterior jugular veins draped between platysma and strap muscles

• Strap muscles (sternohyoid + sternothyroid) separated in midline through superficial layer of deep cervical fascia
• From sternal notch to thyroid cartilage
• Sternohyoid separated from deeper sternothyroid by blunt dissection
• Sternothyroid dissected off thyroid capsule
• For large goiters: transect strap muscles near superior attachment to thyroid cartilage (reapproximate on closure)

• Thyroid retracted anteromedially
• Carotid sheath identified laterally
• Middle thyroid vein identified, ligated and divided

• Expose and dissect the superior pole using blunt dissection
• Downward and lateral countertraction on thyroid
• Vessels dissected individually as far caudally on the gland as possible (to protect EBSLN)
• Superior pole vessels ligated close to the gland (not en masse)
• Critically: identify and protect the EBSLN before ligation of superior pole vessels

• Most important step in thyroid surgery
• Lateral and posterior mobilization of thyroid to identify the tubercle of Zuckerkandl
• RLN identified distal to where it enters the larynx and traced throughout dissection
• Common locations: tracheoesophageal groove (left side), more oblique (right side)
• The RLN crosses the inferior thyroid artery - the artery must not be ligated before RLN is identified
• Intraoperative neuromonitoring (IONM): adjunct, not replacement, for visual identification; stimulation probe used; positive signal (>100 mV amplitude) = nerve intact

• Inferior thyroid artery ligated distal to parathyroid branches (to preserve parathyroid blood supply)
• Halsted's principle: ligate distal branches individually ("ultraligation") not the artery trunk
• This preserves parathyroid blood supply

• Identify all 4 parathyroid glands
• Superior parathyroids: dorsal to RLN, near junction of inferior thyroid artery and RLN
• Inferior parathyroids: ventral to RLN, more variable
• If blood supply is compromised: autotransplantation into sternocleidomastoid muscle (biopsy first to confirm parathyroid; mince into 1mm pieces; place in pockets within SCM)
• Near-infrared autofluorescence (NIRAF): emerging technology to identify parathyroids intraoperatively

• Thyroid attached to trachea by ligament of Berry (posterior suspensory ligament)
• Divided carefully; note: RLN branches may traverse it in 25% of individuals
• Most vulnerable point for RLN injury

• Check all specimen for inadvertent parathyroid tissue
• If parathyroid found: autotransplant into SCM

• Strap muscles reapproximated in midline
• Drain placement (per surgeon preference; not mandatory)
• Platysma closed
• Skin closed

Adjunctive Technologies

• Harmonic scalpel / LigaSure: energy sealing devices for hemostasis; reduce operative time
• IONM: Intraoperative neuromonitoring; NIM EMG ETT; helps identify RLN but does not eliminate injury
• Near-infrared fluorescence: parathyroid identification

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SECTION 9: COMPLICATIONS OF THYROIDECTOMY

Box: Complications of Thyroidectomy (Scott-Brown / Sabiston)

1. Bleeding / Hematoma
2. Recurrent laryngeal nerve injury
3. Hypoparathyroidism / Hypocalcemia
4. External branch of superior laryngeal nerve injury
5. Thyroid storm
6. Wound infection
7. Seroma / Keloid formation
8. Hypothyroidism (after total thyroidectomy)
9. Tracheomalacia (rare; after long-standing goiter)

1. Post-thyroidectomy Hematoma

• Incidence: 0.1-1.1%
• Risk factors: male sex, advanced age, bilateral operation, Graves disease, anticoagulants
• 80% occur in first 6 hours; 20% between 6-24 hours
• Danger: not blood loss but local tracheal compression → airway compromise
• Features: pain, oozing, ecchymosis, firm swelling, stridor
• Management:
  • If impending airway collapse: open incision immediately at bedside (all three layers: skin, platysma, strap muscles)
  • Bedside opening instruments must be at bedside at all times post-thyroidectomy
  • Then take to OR for definitive hemostasis and formal wound closure

2. RLN Injury

• Most feared complication
• Incidence: temporary 1-5%; permanent <1% (high-volume surgeons)
• Higher risk: reoperation, Graves disease, thyroid cancer, substernal goiter
• Unilateral RLN injury: hoarseness, weak voice, aspiration
• Bilateral RLN injury: stridor, respiratory distress - requires urgent tracheostomy
• Prevention: visual identification + IONM + meticulous dissection
• If injury suspected: postoperative laryngoscopy (perform within 24-48 hours)
• Treatment: voice therapy; medialization laryngoplasty (Isshiki type I thyroplasty) for permanent unilateral paralysis

3. Hypoparathyroidism / Hypocalcemia

• Most common complication of total thyroidectomy
• Temporary hypoparathyroidism: 5-15%; resolves within 6 months
• Permanent hypoparathyroidism: 1-3% (if PTH still low at 6 months)
• Risk factors: bilateral neck exploration, central neck dissection, reoperative surgery, Graves disease, pediatric patients
• Symptoms: perioral tingling, carpopedal spasm, Chvostek sign (facial twitching with tapping over facial nerve), Trousseau sign (carpal spasm with inflated BP cuff)
• Management:
  • Mild: oral calcium + calcitriol (vitamin D analog)
  • Severe / symptomatic: IV calcium gluconate (10 mL 10% solution)
  • Long-term permanent: Recombinant PTH (rhPTH 1-34 or 1-84) + calcium + calcitriol
  • Prophylactic calcium: some centers give post-total thyroidectomy; high-risk patients given preoperative calcium too

4. EBSLN Injury

• Rate: 2.5-28%
• Vocal fatigue, loss of high-pitched notes, decreased voice projection
• Often subclinical; laryngoscopy normal; confirm with electromyography

5. Thyroid Storm (Post-operative)

• Can occur if patient inadequately prepared (not rendered euthyroid preoperatively)
• Management as detailed above (PTU, iodine, propranolol, corticosteroids)
• Occurs in hyperthyroid patients undergoing thyroid or non-thyroid surgery

6. Tracheomalacia

• Rare; softening of trachea from prolonged compression by large goiter
• Risk: acute airway collapse after tracheal decompression
• Prevention: preoperative CT to assess; leave ETT in situ postoperatively until trachea stabilizes

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SECTION 10: POSTOPERATIVE CARE

• Routine: oral calcium + vitamin D (especially after total thyroidectomy)
• Monitor: serum calcium at 6-12 hours postoperatively; PTH at 4 hours (low PTH = high risk of hypocalcemia)
• Voice assessment at 24-48 hours (laryngoscopy if hoarse)
• Levothyroxine replacement after total thyroidectomy
• TSH suppression: for high-risk DTC - maintain TSH <0.1 mIU/L
• Radioactive iodine (RAI/I-131): adjuvant for intermediate/high-risk DTC after total thyroidectomy
  • Requires TSH stimulation (>30 mIU/L): stop levothyroxine 4-6 weeks OR use recombinant TSH (Thyrogen)
  • Low-iodine diet 2 weeks before RAI
• Surveillance: thyroglobulin (Tg) + neck ultrasound every 6-12 months

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SECTION 11: ATA GUIDELINES SUMMARY (2015 / 2025)

Thyroid Nodule Management (ATA 2015)

• Ultrasound pattern guides FNA decision:
  • High suspicion pattern (hypoechoic + microcalcifications + taller-than-wide + irregular margins + ETE): FNA if ≥1 cm
  • Intermediate suspicion (hypoechoic, solid): FNA if ≥1 cm
  • Low suspicion (isoechoic/hyperechoic, solid or partial cystic): FNA if ≥1.5 cm
  • Very low suspicion (spongiform): FNA if ≥2 cm
  • Purely cystic: FNA not recommended

DTC Surgical Recommendations (ATA 2015)

• Lobectomy: DTC <4 cm, no ETE, no clinical LN disease, no distant metastases, unifocal
• Total thyroidectomy: tumors >4 cm, high-risk features, bilateral disease, positive nodes, any need for RAI
• Central neck dissection (CND):
  • Therapeutic CND: for clinically involved central nodes (cN1b) - always
  • Prophylactic CND: may be considered for PTC >4 cm or gross ETE; not routinely for T1/T2 tumors without suspicious nodes

RAI Recommendations (ATA 2015)

• Routinely recommended: high-risk disease (extensive ETE, distant metastases, incomplete resection)
• Selectively recommended: intermediate-risk (minor ETE, vascular invasion, >5 LN mets)
• Not recommended: low-risk unifocal microcarcinoma, intrathyroidal PTC <4 cm with favorable histology

Response to Therapy Categories (ATA 2015)

MTC Management

• Total thyroidectomy + central neck dissection for all MTC
• Lateral neck dissection if lateral nodes involved clinically
• Postoperative calcitonin: target undetectable; if elevated = persistent/residual disease
• Systemic therapy: vandetanib or cabozantinib (RET kinase inhibitors) for metastatic MTC

Anaplastic Thyroid Cancer

• If resectable: total thyroidectomy + radiation + chemotherapy
• If unresectable (majority): palliation; airway management; tracheostomy if needed
• BRAF V600E positive (present in ~45%): dabrafenib + trametinib (BRAF/MEK inhibitors)
• Pembrolizumab + lenvatinib: for BRAF-wild-type ATC

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SECTION 12: HIGH-YIELD EXAM MNEMONICS

WHAM - Features of Malignant Thyroid Nodule

• Wood-hard consistency
• History of radiation
• Age extremes (<20 or >70)
• Metastatic lymph nodes

4 P's of Graves Disease

• Palpitations (tachycardia)
• Protrusion (exophthalmos)
• Pretibial myxedema
• Pyramid (diffuse goiter)

Thyroid Storm TREATMENT: "P-PILLS"

• PTU (300 mg q6h)
• Potassium iodide (60 mg q6h - after PTU)
• Inotropes / IV fluids
• Levels (monitor electrolytes)
• Lavorite: Beta-blockers (Propranolol)
• Steroids (Prednisolone 60 mg)

Bethesda III/IV: "Indeterminate - Think Molecular Test"

• Bethesda III = AUS/FLUS → repeat FNA or molecular testing
• Bethesda IV = Follicular Neoplasm → lobectomy (histology needed)

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SECTION 13: EXAM QUESTION BANK

Commonly Examined Questions

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• Sabiston Textbook of Surgery, 21st Edition - Ch. 73 (Thyroid)
• Schwartz's Principles of Surgery, 11th Edition - Ch. 38
• Scott-Brown's Otorhinolaryngology Head & Neck Surgery - Ch. 61
• ATA Management Guidelines for Thyroid Nodules and DTC, 2015 (Haugen et al., Thyroid 2016)
• ATA 2025 Guidelines for Differentiated Thyroid CancerYour credits are exhausted. You can purchase a top-up or subscribe to a plan to continue using Orris. If you're already subscribed, your daily credits will reset tomorrow.