MANAGEMENT OF THYROID NEOPLASMS

In the name of GodIn the name of God

Chapter 119

Department Of Oto-rhino-Laryngology Of Isfahan Medical Science

Approximately 2% of all malignancies, and 90% of all endocrine tumors.

Thyroid nodules, approximately 4% to 7% of the U.S.

5% or so of these patients have a malignant lesion.

The great majority are well-differentiated tumors of

follicular cell origin;

79% papillary, 13% follicular, 3% Hürthle cell and 4%

Medullary cancer.

INTRODUCTION

Medial anlage from the endoderm of the first and second pharyngeal pouches at the foramen cecum and descends

to its adult pretracheal position during weeks 4 to 7 of gestation.

lateral thyroid primordia arise from the fourth and fifth pharyngeal pouches.

Parafollicular C cells arise from the neural crest of the

fourth pharyngeal pouch and infiltrate deep within the middle to upper third of the lateral lobes.

EMBRYOLOGY

Weighing 15 to 25 g. A thyroid lobe usually is about 4 ×1.5 × 2 cm.

Pyramidal lobe in 40% of patients, arises from either lobe

or isthmus and extends superiorly.

Suspensory or Berry's ligament, connecting the lobes of the thyroid to the cricoid cartilage and the first two tracheal rings.

SURGICAL ANATOMY

Inferior thyroid artery from the thyrocervical trunk, primary blood supply for the parathyroid glands.

Superior thyroid artery from the external carotid artery, lies posterolateral to the external branch of the SLN, Care should be taken to ligate this vessel without damaging the SLN.

Thyroid ima artery from the innominate, carotid, or aortic arch and supply the gland near the midline.

SURGICAL ANATOMY…

SURGICAL ANATOMY…

RLN provides motor supply to the larynx and some sensory function to the upper trachea and subglottic area .

On the right side, it recurs around the fourth arch

(subclavian artery) and back into the thyroid 2 cm lateral to the trachea & enters the larynx between cricoid cartilage and the inferior corn of the thyroid cartilage.

On the left side, it recurs around the sixth arch (lateral to the ligamentum arteriosum). It travels posterior to the carotid sheath and near the tracheoesophageal groove.

“Nonrecurrent" laryngeal nerve rarely on the right side and has a more lateral course. An aberrant retroesophageal subclavian artery (arteria lusoria).

SLN medial to the carotid sheath, dividing into internal and external branch about 2 cm above the superior pole.

Internal branch enters through the posterior thyrohyoid membrane to supply sensation to the supraglottis .

External branch enters the cricothyroid muscle. It diverges from the superior thyroid vascular pedicle about 1 cm from the thyroid superior pole.

SURGICAL ANATOMY…

Superior parathyroid from the fourth pharyngeal pouch, and inferior from the third. weighing 30 to 70 mg.

80% have four glands and at least 10% have more than four glands.

The superior glands at the level of the cricoid cartilage, usually medial to the intersection of the RLN and the inferior thyroid artery.

The inferior glands are more variable in location. may be on the lateral or posterior surface of the lower pole.

SURGICAL ANATOMY…

RISK FACTORS

Dietary iodine iodine has no association with thyroid carcinomas.

GoiterGoiter has association with follicular and anaplastic but not with papillary.

RadiationRadiation risk is greatest in <10 Y, and no risk in >20 Y. If

history of radiation + the risk of malignancy is 50%. The most is papillary and frequently multifocal (40% located extra nodular), higher risk of cervical metastases.

Family historyFamily history of breast, ovarian, renal & central nervous system malignancies in papillary. Gardner's syndrome (familial colonic polyposis) and Cowden's disease in well-differentiated thyroid carcinomas.

FACTORS USED IN PROGNOSTIC CLASSIFICATION SYSTEMS

TNM AMES AGES MACIS

Patient factors

Age * * * *

sex * *

Size * * * *

Tumor factors

Histologic grade *

Histologic type * * + +

Extrathyroidal spread * * * *

Lymph node metastasis *

Distant metastasis * * * *

Incomplete resection *

+ AGES/MACIS classifications for papillary carcinomas only.

 RISK FACTORS FOR AGGRESSIVE BEHAVIOR

Patient factors History

Age:  <20 y ,  male>40 y  &  female>50 y

Gender:  Male > female

 History of radiation

Family history of thyroid carcinoma

Physical examination

Hard, fixed lesion

Rapid growth of mass

Pain

Lymphadenopathy

Vocal cord paralysis

Aerodigestive tract compromise 

 Dysphagia  

Stridor

Histopathologic factors (at initial presentation)

Size (>4 cm)

Extrathyroidal spread

Vascular invasion

Lymph node metastasis

Distant metastasis

Histologic type

    Tall-cell variant of papillary  

  Follicular carcinoma 

  Hürthle cell carcinoma

Diagnostic Studies

Laboratory Studies ;

The majority of patients with a thyroid nodule are euthyroid.

Hypo or hyperthyroidism shift the workup to a functional disorder such as Hasimoto's thyroiditis or a toxic nodule.

Thyroglobulin is secreted by both normal and malignant cells. extremely high level seen in metastatic thyroid cancer. Its levels is useful in patients who have undergone total thyroidectomy.

Serum calcitonin level is measured in patient with family history of medullary cancer or MEN II & if FNAC demonstrates or is suspicious for medullary thyroid carcinoma.

Diagnostic Studies…

Fine-Needle Aspiration Cytology;

It is highly sensitive and specific.

15% of all aspirates are inadequate or nondiagnostic, Reaspiration is critical, surgical diagnoses following repeated nondiagnostic aspirations revealed malignant nodules in 4% of women and 29% of men.

False-negative rate is 1% to 6% and false-positive is < 5% (most in patients with Hashimoto's thyroiditis, Grave's disease, or toxic nodules).

Follicular and Hürthle cell neoplasms cannot be classified by FNAC alone and requires evaluation of the entire thyroid nodule. Carcinomas can be found in up to 20% of nodules diagnosed as Follicular or Hürthle cell neoplasms by FNAC.

Diagnostic Studies…

Imaging

Ultrasonography in nonpalpable nodules & difficult neck to examine (previous head and neck irradiation), differentiation between cystic and solid nodules, identifying hemiagenesis and contralateral lobe hypertrophy, evaluation of cervical LAP in patients with history of thyroid cancer. are not usefulare not useful in evaluation of substernal extent or the involvement of adjacent structures.

CT scan and MRI scans in large or retrosternal lesions.

Diagnostic Studies…

Thyroid Isotope Scanning

The incidence of malignancy in cold nodules was 10% to 15%, but only 4% in hot nodules.

99mTc only tests iodine transport Cold nodules is cold in iodine scanning but any "hot" nodules require 123I scanning for confirmation. It is performed in 1 day with less radiation exposure. can not penetrate the sternum so is not useful in confirming substernal extension.

123I scanning tests both transport and organification. Is performed in 2 days. Cold lesions is visualized difficult, oblique views improve detection.

THYROID NEOPLASMS

Thyroid Adenoma

Common in women > 30 Y. present with a solitary, mobile nodule not associated with any other signs or symptoms. Sudden hemorrhage increase the size and associated pain.

FNA demonstrates follicular neoplasm surgical excision &…

Tx is thyroid lobectomy. in head-and-neck radiation, other head and neck cancers, potential high-risk factors, and comorbidities, total thyroidectomy.

In autonomously hyperfunctioning adenomas, surgery (unilateral lobectomy in < 40 Y) and radioiodine therapy or Ethanol injection can be used .

THYROID NEOPLASMS…

Thyroid Cyst

15% to 25% of thyroid nodules are cystic or have a cystic component.

Majority are benign adenomas or colloid nodules although papillary carcinomas and parathyroid tumors may present with cystic masses. Papillary carcinoma in 14% to 32% of all cystic nodules.

If a cyst persists after three drainage or reaccumulates quickly ultrasound-guided FNA to sample a solid component or thyroid lobectomy.

Red fluid is more suspicious for carcinoma. Clear, colorless fluid can be assessed for PTH.

THYROID NEOPLASMS…

Papillary Carcinoma

The most common form in adult (60 - 70%) and children (75%). children usually present with advanced disease but their prognosis remains quite favorable.

Minimal or occult/microcarcinoma; up to 1.5 cm, usually are incidental findings during operation or autopsy.

Intrathyroid tumors ; > 1.5 cm, no evidence of extrathyroid invasion.

Extrathyroid tumors; extend through the thyroid capsule.

Strong lymphotropic nature; 30% clinically positive, 50 - 80% microscopically & up to 80% contralateral lobe involement, but clinical recurrence is < 10%.

Papillary carcinoma…

management

In minimal papillary carcinoma, unilateral lobectomy and isthmusectomy is sufficient unless there is angioinvasion or positive margins. They should be treated with thyroid hormone.

In more extensive disease and high-risk patients, total or near-total thyroidectomy + thyroid hormone & radioiodine. F/O thyroglobulin levels, which should remain undetectable.

If palpable or visible node selective neck dissection (levels II–V).

If primary tumor > 2 cm or extrathyroid involvement levels VI and VII carefully inspected and palpated….

THYROID NEOPLASMS…

Follicular Carcinoma

10% of thyroid malignancies.

mean age of presentation is higher than papillary carcinoma

(50Y versus 35Y).

Cervical LAP is uncommon, distant metastases are more frequently encountered than with papillary.

Complete capsular evaluation must be performed frozen-

section analysis is inadequate lobectomy / isthmusectomy.

Follicular carcinoma… management

Complete thyroidectomy unless minimally invasive carcinoma (evidence of invasion into but not through the tumor capsule at one or more sites) that lobectomy may be sufficient treatment.

Frozen sections useful to confirm gross evidence of adjacent

cervical LAP.

In older patients with a nodule greater than 4 cm, diagnosed by FNAC as follicular neoplasm total thyroidectomy is performed (risk of carcinoma is 50%).

Neck dissection is performed if cervical lymphadenopathy is present.

THYROID NEOPLASMS …

Hürthle Cell Tumor

Is a subtype of follicular cell neoplasm but more aggressive.

More in Hashimoto's thyroiditis or Graves' disease or within a nodular goiter.

Derived from oxyphilic cells, express TSH receptors and produce thyroglobulin.

Lobectomy/ isthmectomy total thyroidectomy. less amenable to radioiodine.

TSH suppression and thyroglobulin monitoring.

THYROID NEOPLASMS …

Medullary Carcinoma 5% of all thyroid carcinomas, from parafollicular C cells, may

secrete calcitonin, CEA, histaminadase, prostaglandins, and serotonin.

Intermediate behavior between well-differentiated carcinoma and anaplastic carcinomas. F=M.

May present along with papillary carcinoma because ret mutation presents in both.

30% are familial (autosomal-dominant with 100% penetrance, in younger patients ).

MEN IIA; MTC, pheo and ↑PTH. MEN IIB; MTC, pheo, mucosal neuromas & marfanoid body.

Medullary Carcinoma… management

FNAC diagnosis of MTC serum calcitonin & ret mutation. Careful family screening in hereditary form of MTC.

Total thyroidectomy is choice, in patients with FMTC or MENII even in the absence of a palpable mass.

Palpable node central compartment and comprehensive neck dissection.

Clinically negative central and elective, ipsilateral neck dissection.

Contralateral neck dissection in all patients especially in > 2cm lession.

EBRT is controversy for positive margins or unresectable tumor, there is no effective chemotherapy.

THYROID NEOPLASMS …

Anablastic Carcinoma

One of the most aggressive malignancy, few patients surviving 6 months beyond initial presentation.

In 80% is transformation of a well-differentiated thyroid cancer.

Formal biopsy is necessary to exclude lymphoma.

Surgical debulking for palliation + tracheostomy and nutritional support (doxorubicin, hyperfractionated radiation therapy)

Other Forms of Thyroid Cancer Insular Thyroid Carcinoma

Clusters of cells contain small follicles resembling pancreatic islet cells.

Very aggressive compared with follicular and papillary carcinoma when present as an independent process but dose not

affect the clinical course of papillary & follicular carcinoma. Lymphoma

< 5% of all thyroid malignancies. F>M. more in patients with hypothyroidism (Hashimoto's disease).

Non-Hodgkin's B-cell lymphoma is the most common. surgury in airway obstruction that do not respond rapidly to

treatment.

Other Forms of Thyroid Cancer… Metastatic Carcinoma

Is rare. The most is hypernephroma, 3% of bronchogenic carcinomas metastasize to the thyroid but account for 20% of all metastases to the thyroid.

FNAC diagnosis is definitive. Thyroidectomy for palliation, especially when the primary

lesion is very slow growing renal cell carcinoma. Squamous Cell Carcinoma

very rare, metastasis from upper aerodigestive tract needs to be excluded.

Tx is aggressive surgry + radiation therapy .

SURGICAL MANAGEMENT

Indirect laryngoscopy & medical therapy of thyrotoxicosis or hypothyroidism.

Transverse incision 1 cm below the cricoid. Subplatysmal skin flaps, superiorly to the level of the thyroid cartilage notch and inferiorly to the clavicle.

Dissection proceeds laterally until the ansa cervicalis is noted.

The superior pole vessels are isolated for ligation close to the thyroid capsule to avoid injury to the external branch of the SLN.

SURGICAL MANAGEMENT…

RLN triangle; trachea medially, carotid sheath laterally, and the undersurface of the retracted inferior thyroid pole superiorly. dissection should be parallel to the course of the RLN.

RLN, in large thyroid mass, can be fixed to and splay across the undersurface of the enlarged thyroid lobe superior approach identifying the RLN at its entry into the larynx.

RLN is tethered down by the Berry's ligament. Use of electrocautery in this region should be strictly avoided.

SURGICAL MANAGEMENT…

Substernal goiters with previous thyroid surgury, invasive malignant tumors, no thyroid tissue in the neck requires median sternotomy & if it is too large to deliver through a cervical incision.

In well-differentiated thyroid carcinomas, there is no survival difference between RLN sacrifice and postoperative radioiodine. in medullary carcinoma, RLN sacrificed to achieve complete removal of gross disease.

Reoperation should be performed within 3 to 4 days or after 3 months. RLN should be followed from a previously undissected area into the surgical bed. Intraoperative monitoring of the RLN can be helpful.

Treatment in pregnancy Beyond 20 weeks of gestation deferred FNAC until after the

pregnancy unless nodule continued growth or other suspicious features. Others advocate immediate FNAC at any stage of pregnancy.

If FNAC is benign F/U with ultrasonography. If follicular neoplasm close F/U or surgury. If suspicious or carcinoma surgery

Carcinomas identified late in pregnancy treated in immediate postpartum period.

In first and early second trimesters during the 22nd through 26th gestational weeks.

Aggressive carcinomas that grow rapidly or invade adjacent cervical structures may demand immediate surgical attention.

Medullary or undifferentiated carcinoma the pregnancy should be terminated.

Complications… Bleeding

Can lead to life-threatening airway compression immediate opening of incision and evacuation of blood, Airway control can then be established.

Wound seroma after the removal of a large goiter simple needle aspiration manages the problem and prevent the infection

SLN injury

alter function of the cricothyroid muscle difficulty shouting, and singers will find difficulty with pitch variation, especially in the higher frequencies.

Complications… RLN Injury

Permanent paralysis is 1% - 1.5% for total thyroidectomy and less for near-total procedures.

Unilateral injury TVC in the paramedian position & breathy voice and lack volume.

Bilateral RLN injury Immediate postoperative stridor and dyspnea & immediate reintubation or tracheostomy.

RLN + SLN more laterally positioned TVC, patients may have aspiration and pneumonia.

If the nerve is transected during surgery, microsurgical repair may decrease the extent of vocal cord atrophy. Some advocate anastomosis of the ansa hypoglossal nerve to the distal end of the severed RLN to prevent laryngeal synkinesis and possible vocal cord hyperadduction.

Complications… Hypocalcemia

Perioral and distal extremity paresthesias continue with tetany, bronchospasm, mental status changes, seizures, laryngospasm, and cardiac arrhythmias. Chvostek's sign and Trousseau's is + in ca < 8.0 mg/dL.

Ca should measure in the immediate postoperative period and the next morning in total thyroidectomy.

If it is symptomatic or ca < 7.0 mg/dL cardiac monitoring + 10 mL of 10% calcium gluconate and 5% dextrose in water intravenously.

Oral calcium supplementation begins with 2 to 3 g of calcium carbonate per day + calcitriol.

POSTOPERATIVE MANAGEMENT

Thyroid Hormone Replacement levothyroxine to suppress TSH below-normal levels. Immediately postoperative, liothyronine sodium (T3) decreases the

waiting period before radioiodine body scanning.

Radiation Treatment 131I isotope in high-risk papillary carcinoma, follicular carcinoma &

despite poor radioiodine uptake in Hürthle cell and medullary carcinomas.

Elevated TSH is necessary to enhance uptake of iodine by thyroid cancer cells taken off thyroid hormone therapy for 4 to 6 weeks before scanning and placed on a low-iodine diet.

Exogenous TSH is safe and effective for stimulating radioiodine uptake and for detecting serum thyroglobulin.

Don’t wait for what you want, Go after it with all that you are.