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Thyroid Disease2
Thyroid Disease2
Thyroid Disease2
Thyroid Disease2
Thyroid Disease2
Thyroid Disease2
Thyroid Disease2
Thyroid Disease2
Thyroid Disease2
Thyroid Disease2
Thyroid Disease2
Thyroid Disease2
Thyroid Disease2
Thyroid Disease2
Thyroid Disease2
Thyroid Disease2
Thyroid Disease2
Thyroid Disease2
Thyroid Disease2
Thyroid Disease2
Thyroid Disease2
Thyroid Disease2
Thyroid Disease2
Thyroid Disease2
Thyroid Disease2
Thyroid Disease2
Thyroid Disease2
Thyroid Disease2
Thyroid Disease2
Thyroid Disease2
Thyroid Disease2
Thyroid Disease2
Thyroid Disease2
Thyroid Disease2
Thyroid Disease2
Thyroid Disease2
Thyroid Disease2
Thyroid Disease2
Thyroid Disease2
Thyroid Disease2
Thyroid Disease2
Thyroid Disease2
Thyroid Disease2
Thyroid Disease2
Thyroid Disease2
Thyroid Disease2
Thyroid Disease2
Thyroid Disease2
Thyroid Disease2
Thyroid Disease2
Thyroid Disease2
Thyroid Disease2
Thyroid Disease2
Thyroid Disease2
Thyroid Disease2
Thyroid Disease2
Thyroid Disease2
Thyroid Disease2
Thyroid Disease2
Thyroid Disease2
Thyroid Disease2
Thyroid Disease2
Thyroid Disease2
Thyroid Disease2
Thyroid Disease2
Thyroid Disease2
Thyroid Disease2
Thyroid Disease2
Thyroid Disease2
Thyroid Disease2
Thyroid Disease2
Thyroid Disease2
Thyroid Disease2
Thyroid Disease2
Thyroid Disease2
Thyroid Disease2
Thyroid Disease2
Thyroid Disease2
Thyroid Disease2
Thyroid Disease2
Thyroid Disease2
Thyroid Disease2
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Thyroid Disease2

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  • 1. Thyroid disease
    • Gross anatomy
    • The normal adult thyroid weights approximately 15 to 20 gm,has two lateral lobes, 4cm long and 2cm wide. The isthmus joins the two lobes, just below the cricoid cartilage. The thyroid is surrounded by a thin fibrous capsule that is reinforced posteriorly attachment to the trachea and larynx.
  • 2.
    • The normal thyroid moving with the larynx during swallowing.
    • Blood supply
    • Inferior thyroid artery ---is a branch of the subclavian artery.
    • Superior thyroid artery---arising from the external carotid artery.
    • The venous drainage is from three veins—superior, middle, and inferior.
    • There are four parathyroid glands, but there may be as many as seven.
  • 3. Nerve government
    • Recurrent laryngeal nerve lies adjacent to the postromedial aspect of the thyroid near the small groove between the lateral aspects of the trachea and esophagus. This nerve contains the motor fibers innervating the abductor muscles of the true vocal cords.
  • 4.
    • The external branch of the superior laryngeal nerve, is another easy injury nerve during thyroidectomy, this nerve was found in intimate proximity to the superior thyroid artery and vein.
  • 5.  
  • 6.  
  • 7.  
  • 8. Physiology
    • The thyroid gland functions primarily to produce thyroid hormone for development and regulation of metabolism.
    • Thyroid hormone production is under the regulation of the anterior pituitary hormone thyrotropin, or thyroid-stimulating hormone(TSH), and by a system of autoregulation within the thyroid gland.
  • 9. Hyperthyroidism
    • Etiology
    • 1.Due to excess circulating thyroid hormone. Diffuse toxic goiter( Graves’s disease) and toxic nodular Goiter( Plummers’s disease) account for most cases.
    • 2. Autoimmune disorder: it is considered that the LATS(long acting thyroid stimulator) and TSI ( thyroid stimulating immunoglobulin) two antibodys found in primary hyperthyroidism are related with autoimmune disease.
  • 10.
    • 3.Secondary hyperthyoidism.
    • Classification
    • 1.Primary hyperthyroidism
    • 2. Secondary hyperthyroidism
    • 3.Hyperfunctional adenoma.
    • .
  • 11.
    • Clinical manifestation
    • 1. Thyroid: The thyroid of primary hyperthyroidism is enlarged diffusely
  • 12.
    • The quantity of blood entering to normal thyroid is about 50-60ml/min, in severe PTH it may increased up to 1000ml/min.
    • 2.CNS: Such as irritability, sweating, heat, hand thrill, insomnia, warm, thin, moist .
    • 3. Eye,The typical signs are exophathalmos and mydriasis.
  • 13.
    • 4.Circulatory system: Systolic pressure high, diastolic pressure low, wide pulse pressure. High pulse rate. Dilation hypertrophy of heart,in severe case, arrhythmia, artrial fibrillation and heart failure.
    • 5.BMR(Basal metabolic rate) usually increase.
    • 6. Other: Weight loss, diarrhea, thin hair, increased appetite and muscle weakness.
  • 14. Diagnosis
    • 1. History
    • 2.Clinical findings
    • 3.BMR BMR=(pulse+pulse pressure)-111
    • Normal BMR is +10%
    • Mild hyperthyroidism: 20-30%
    • Moderate hyperthyroidism:30-60%
    • Severe hyperthyroidism: above 60%
  • 15.
    • 4. 131 I uptake test
    • Normal: 30-40%/24hour
    • Hyperthyroidism(1)uptake peak appears ahead.
    • (2) >25%/2hours
    • (3)>50%/24hours
    • 5.T 4 and T 3 increase, T 3 is more sensitive than T 4
  • 16.
    • In mild forms of hyperthyroidism, the usual diagnostic laboratory tests are likely to be only slightly abnormal. In these difficult to diagnose cases, two additional tests are helpful: T3 suppression test and the TRH test. In the T3 suppression test, hyperthyroid patients fail to suppress the thyroidal uptake of radioiodine when given exogenous T3. In the TRH test, serum TSH levels fail to rise in response to administration of TRH in hyperthyroid patients.
  • 17. treatment
    • 1.antithyroid drugs.
    • Propylthiouracil 300-1000mg orally daily
    • Methimazole (Tapazole) 30-100mg orally daily. The goal is to maintain the patient in a euthyroid state. Administered for 18-24 months. Reliable patients with small goiters are good candidates for this regimen.
  • 18.
    • A prolonged remission after 18 months of treatment occurs in 30% of patients, some of whom eventually become hypothyroid. Side effects include rashes and fever(3-4%) and agranulocytosis(0.1-0.4%).
  • 19. B Radioiodine
    • Radioiodine ( 131 I) may be given safely after the patient has been treated with antithyroid medications and has became euthyroid. Radioiodine is indicated for patients who are over 40 or are poor risks for surgery and for patients with recurrent hyperthyroidism. To date, radioiodine treatment at doses necessary to treat hyperthyroidism had not been associated with an increased in leukemia or the induction of congenital anomalies.
  • 20.
    • However, an increased incidence of benign thyroid tumors and rare cases of malignant thyroid tumors have been noted to follow treatment of thyperthyroidism with radioiodine. In young patients, the radiation hazard is certainly increased, and the chance of developing hypothyroidism is virtually 100%. Hyperthyroid children and pregnant women should not be treated with radioiodine.
  • 21. Surgical treatment
    • Indications
    • (1)secondary hyperthyroidism
    • (2)Hyperfunctional adenoma
    • (3) Moderate and severe cases in PHT
  • 22.
    • (4) Large thyroid gland with pressure symptom or poststernal thyroid gland.
    • (5) Recurrent hyperthyroidism after treatment by 131I or antihyperthyroidism drugs.
    • Contraindications
    • (1) younger patient
    • (2) Mild cases
    • (3)In elderly patient or/with severe disease who can not tolerate the operation.
  • 23. Subtotal thyroidectomy
    • Preoperative examination:
    • 1.Neck X-Ray: to check whether the trachea is pressed.
    • 2.Laryngoscopy: to check the function of vocal cord.
    • 3.BMR:to know the extent of hyperthyroidism.
  • 24.
    • 4.T3 and T4
    • 5. Serum Ca 2+ and P 3 –
    • Preoperative preparation
    • 5droups of Lugol’s solution( a combination of potassium iodide, 10 gm per 100gm, and iodine 5g per 100gm).for 10 days to decrease the “vascularity” of the gland.. Beta-receptor blockade, while effectively controlling the heart rate,tremor and anxiety.
  • 25.
    • The patient must satisfied the following indices before operation.
    • 1. Pulse below 90/min
    • 2.BMR below 20%.
    • 3.Symptoms of hyperthyoidism nearly disappear.
    • 4good sleep, weight gain and no restlessness.
  • 26. Main complications after operation
    • 1. Dyspnea and asphyxia due to
    • (1) Haemorrhage and hematoma
    • (2) Laryngeal edema.
    • (3)Tracheal obstruction due to collapse.
    • (4) Bilateral recurrent nerve injury, with acute paralysis of both vocal cord, and require emergency tracheostomy.
  • 27.
    • 2.Injury of upper laryngeal nerve.
    • 3. Injury of recurrent laryngeal nerve lead to hoarseness.
    • 4. Injury of parathyroid gland: Hypocalcemia.
    • 5 Thyroid crisis.
  • 28. Goiter
    • Etiology
    • 1. Insufficiency of iodine: endemic goiter
    • 2. The period when the need of iodine increase relatively, such as puberty, pregnancy, menopausal and developing phase.
    • 3.It may be caused when interference is present in process of synthesis and release of thyroid.
  • 29.
    • 4.some food as cabbage and turnip contain thiorea which is an inhibition element of thyroid and due to excess use of antithyroid drugs
    • Anatomical changes: are divided into two kinds.
    • (1) diffuse goiter: it is present in puberty.
    • (2) nodular goiter: it is common in endemic region and due to the bad blood supply. Regression may be occur such as cyst, fibrosis, calcification.
  • 30. Clinical manifestation
    • Local symptoms: generally there are no symptoms. BMR is normal, Neck mass should checked.
    • 2. Pressure symptoms:
    • The trachea is pressed commonly, It is severe in posternal goiter. Long standing goiter may lead to tracheomalacia, tracheal deviation and compression.
  • 31.
    • 3. There may be enlargement of cervical vein.
    • 4. Hoarseness can be caused when the recurrent nerve is pressed.
    • 5. When the sympathetic ganglion and chain are pressed, Horner’s syndrome may be cause. E.g. pupil shink, ptosis of eyelid, invagination of the eyeball and decrease of sweating on same side.
  • 32. Diagnosis
    • 1. Case history.
    • 2. Clinical findings.
    • 3. Mass in area of thyroid
    • (1)Moves on swallowing
    • (2) Normal Bp, P, BMR, T3 and T4.
    • (3) Radioactive iodine uptake rate and scaning.
  • 33.
      • (4)Ultrousand.
      • (5) Needle puncture.
      • Treatment
      • Goiters in puberty and pregnancy can be treatment by food abandant in iodine .
      • For those goiter patients younger than 20 years, thyroidin can be given rather than operation. The ordinary dose is 30-60mg tid po. 3-6 months complete a course.
  • 34. Indication of operation.
    • 1. Goiters with pressure symptoms.
    • 2.Post-sternal goiter.
    • 3. Giant goiter influencing daily life and work.
    • 4. Goiters with secondary hyperthyroidism.
    • 5. Suspect of malignancy.
  • 35. Thyroiditis
    • Hashimoto’s disease In hashimoto’s disease, thyroid tissue damaged by immunologic factors is replaced by lymphocytes, plasma cells, and fibrosis.
    • Clinical feature: Symptoms of hypothyroidism in association with a painless, firm goiter are frequent presenting complaints, Large goiters may be associated with pressure symptoms in the neck.
  • 36.
    • Treatment of Hashimoto's thyroiditis is to take thyroid hormone replacement (thyroxine) as soon as the diagnosis is made, even if thyroid function is, at that time, normal. Thyroid hormone is given for three reasons:
    • it shrinks the goitre by suppressing production of thyroid stimulating hormone (TSH) by the pituitary gland;
  • 37.
    • it anticipates the development of thyroid failure and the resulting low levels of thyroid hormone since the disease may progress with time;
    • it seems to have an effect on blood lymphocytes which cause the damage and destruction in the thyroid gland.
  • 38. Treament
    • Surgical reduction of the goiter should be performed if severe pressure symptoms that have not responded to corticosteriod therapy are present.
  • 39. De Quervain’s (Subacute) Thyroiditis
    • Clinical feature: Pain in the thyroid gland often develops rather suddenly, often with radiation to the jaw and ears and may be associated with marked tenderness and dysphagia.
    • Treatment: analgesics auch as aspirin or ibuprofen in mild cases, Steroids are effective in controlling symptoms in the more severs cases.
  • 40. Acute suppurative thyroiditis
    • Due to bacterial infection. Common pathogens include Streptococcus, Staphylococcus and Pneumococcus, and rarely Salmonella or Bacteroides.
    • Clinical: Tenderness, enlargement, warms, erythema, and neck pain exacerbated by neck extension and swallowing.
  • 41. Treatment
    • .appropriate antibiotics against the causative organism. Thyroid abscesses should be drained.
  • 42. Thyroid carcinoma
    • About 4% to 7% of the population has nodular thyroid disease. Approximately, 4% of these nodules are malignant and account for about 1% of all cancers. The incidence of thyroid nodules in female to male is 6.5% to 1.5%. However, the risk of being malignant thyroid nodules is twice as high in males as compare to females. Thyroid cancer develops most commonly between the ages 40 through 60.
  • 43.
    • I. Adenomas     A. Follicular         1. Colloid variant         2. Embryonal         3. Fetal         4. Hurthle cell variant     B. Papillary (probably malignant)     C. Teratoma
  • 44. Thyroid carcinoma
    • A. Differentiated         1. Papillary adenocarcinoma             a. Pure papillary adenocarcinoma             b.Mixed papillary and follicular carcinoma                 (variants including tall cell, follicular, oxyphyl, solid)         2. Follicular adenocarcinomas (variants: "malignant                 adenoma", Hurthle cell carcinoma or oxyphil                 carcinoma, clear-cell carcinoma, insular carcinoma)     B. Medullary carcinoma
  • 45.
    • C. Undifferentiated         1. Small cell (to be differentiated from lymphoma)         2. Giant cell         3. Carcinosarcoma D. Miscellaneous         1. Lymphoma, sarcoma         2. Squamous cell epidermoid carcinoma         3. Fibrosarcoma         4. Mucoepithelial carcinoma         5. Metastatic tumor
  • 46. Papillary Thyroid Carcinoma
    • Papillary Thyroid Carcinoma (PTC): is the most common, accounting for 75% to 80% of thyroid cancer and 80% to 90% of radiation induced thyroid carcinomas. Female to male ratio is 3 to 1. Peak incidence is in the 30s to 40s year of age, with prolonged course and rarely caused death (1% - 10%). The 10-year survival rate is from 84% to 90%.
  • 47.
    • According to the size and location of the tumors, there are three subclasses of papillary carcinomas (1) occult or less than 1.5 cm, (2) intrathyroidal, (3) extrathyroidal. The majority of papillary tumors are nonencapsulated, usually invade lymphatics and replace normal thyroid tissue.
  • 48.
    • Multicentricity develops in 75% of tumors, especially in patients with prior exposure to ionizing radiation. Papillary carcinomas have increased incidence in familial adenomatous polyposis syndromes such as Gardber’s and Cowden’s.
  • 49. Follicular Thyroid Carcinoma
    • Follicular Thyroid Carcinoma (FTC) accounts for 5% of all thyroid cancers and 15% of primary epithelial malignant tumors of the thyroid,. Peak incidence is in the fifth decade of life and female-to-male rate is 3:1. Follicular carcinoma tends to slow enlarging of non-tender nodules, hematogenous metastases to lung, bone and brain.
  • 50.
    • Non-invasive tumors have a 10-year survival rate 86%, whereas invasive tumors have that of 44%. Grossly, follicular carcinomas are usually well encapsulated and grow in an expansive fashion. They undergo cystic degeneration, calcification, or hemorrhage. Follicular carcinoma is more aggressive than papillary carcinoma and is associated with a higher morbidity due to more rapid metastasis.
  • 51. Medullary Carcinoma
    • Medullary Carcinoma (MTC) accounts for 5% to 10% of thyroid cancer. The tumor originates from calcitonin-producing parafollicular C-cell. Grossly, medullary tumors are gray to yellow, firm, well-circumscribed or invasive with bilateral multicentric involvement. Medullary carcinomas are classified as two groups:
  • 52.
    • Sporadic (80%) : have a poorer prognosis, usually unifocal, not associated with other endocrine tumors, occur in middle age to elderly patients, equal in both sexes; single nodule is common in sporadic form with clusters of cells and stromal amyloid in 85% to 90% cases,
  • 53.
    •   Family trait (20%) : autosomal dominant inheritance, tumors associated with C-cell hyperplasia or the calcitonin-producing lesions; these tumors usually have early high calcitonin screening and better prognosis. The familial form of medullary cancers usually develop in the third decade of life with the female to male rate is 1.5 to 1. The familial medullary carcinomas are associated with other endocrine tumors such as:
  • 54.
    • (1) Sipple’s syndrome or multiple endocrine neoplasm type II (MEN IIa), including (a) medullary thyroid carcinoma or C-cell hyperplasia, (b) adrenal medullary carcinoma and (c) hyperparathyroidism.
  • 55.
    • Wermer’s syndrome (MEN IIb), including (a) medullary thyroid carcinoma, (b) pheochromocytoma, (c) mucosal neuromas (of the tongue, lips, conjuctivae), ganglioneuromas of the intestines, characterized by special facial appearance, and marfanoid habitus.
  • 56.
    • Overall prognosis of MTC is poor due to early metastases to lymph nodes and distant metastases. The five-year survival rate is in the range of 60% to 70% and 10 year-survival rate is 40% to 50%. About 50% of medullary cancers have regional metastases to local lymph nodes at the time of diagnosis. Distant metastases include lung, liver, adrenal glands, and bones (osteoblastic, opposed to other cancers, e.g. prostate cancer, osteolysis).
  • 57.
    • Anaplastic Thyroid Carcinoma (ATC) or undifferentiated carcinoma accounts for 3% of all thyroid cancers, more common in elderly patients usually in their seventh decade. Females are more affected than males. Tumors have higher incidence in patients with pre-existing multinodular goiter (30%). The anaplastic thyroid cancer is the most aggressive thyroid cancer, is unencapsulated, and is associated with extended invasion outside the gland.
  • 58.
    • Grossly, the neoplasm has fleshy, tan-white appearance, with hemorrhagic and necrotic areas. Histological cells with spindle or giant-cell variants. Patients with the anaplastic thyroid carcinomas have poor prognosis. Patients usually die within several months, dues to airway obstruction, vascular invasion, distant metastases to lung and bone and resistant to the therapy.
  • 59. Diagnosis
    • The most common diagnostic measures include needle biopsy or aspiration, thyroid blood study, radiology imaging. Needle biopsy, a superior diagnostic technique, which provides accurate cytologic finding with no morbidity, has become the first step in thyroid nodule workup.
  • 60.
    •   History and physical examination: a thorough history and head and neck examination should be the first evaluation of a thyroid mass. A malignant thyroid nodule usually presents as a painless mass. Other symptoms such as pain, hoarseness, dysphagia, dyspnea, stridor, hemoptysis, and rapid enlargement of the mass may occur with thyroid carcinomas but are not necessarily to be the signs of malignancy.
  • 61.
    • Blood test: thyroid function tests include (1) thyroxin or T4, (2) triiodothyronine or T3, and (3) thyroid stimulating hormone or TSH. Serum calcium and phosphorous levels may indicate hyperfunction of parathyroid gland adenoma, which may be associated with thyroid gland malignancy. Thyroglobulin (Tg) is usually measured as a baseline before and following up after surgery of well-differentiated thyroid carcinomas because it correlates with histologic types of tumors.
  • 62.
    • Recurrent tumors are usually associated with high Tg level. Calcitonin is a useful test for diagnosis and screening in patients with medullary thyroid carcinoma and their family members; however, it is not a work up test. Antimicrosomal and anti-Tg antibody titer are unrealistic tests for screening or following up a thyroid cancer because of high cost and low-specificity.
  • 63. Imaging studies:
      • Ultrasonography: is one of the most sensitive and effective tests for differentiation a thyroid and non-thyroid nodule in more than 80% of cases. It provides an accurate tri-dimensional location, follows up the nodular size, and indicates nodular location for the fine needle aspiration. US can detect the nodules as small as 2 to 3 mm and differentiate between solitary and multinodular diseases.
  • 64.
    • Radioisotope Scanning: to evaluate uptake of radioactive iodine or technetium of thyroid nodules compared with the remainder of the thyroid gland. Scintilation scanning has some value for routine evaluation of solitary thyroid nodules because the majority of both benign and malignant thyroid nodules are hyporeactive compared to adjacent tissues. Scanning with 123-I is more accurate but of greater cost and increases radiation exposure to the thyroid gland.
  • 65.
      • Magnetic resonance imaging (MRI): is very useful to detect residual, recurrent and metastatic cancers. T2 imaging is useful in differentiation between tumors and fibroses in operated neck tissue, and detection of muscle invasion. MRI also shows tracheal displacement and vascular relationship involved with large masses. Fat-saturation MRI can be used in suspected recurrent tumors, which are not identified by radioiodine scan.
  • 66.
      • Chest x-ray is helpful in detecting tracheal deviation, airway narrowing, and existent lung and bone metastasis. Patterns of calcification on chest x-ray are useful in identifying the types of cancer: (1) rim or eggshell calcification suggests a benign lesion, (2) bilateral calcification in superolateral aspect of the thyroid gland indicates MTC and (3) extensive irregular calcification suggests a multinodular goiter.
  • 67. Staging of thyroid cancer
    • Staging is determined by physical exam, thyroid imaging, and endoscopic examination:
    • Primary tumor:
      • TX: primary tumor cannot be assessed
      • T0: no evidence of primary tumor
      • T1: Tumor is limited to the thyroid and <1 cm
      • T2: Tumor is limited to the thyroid and >1 cm but <4 cm
      • T3: Tumor is limited to the thyroid and >4 cm
      • T4: Tumor of any size extending beyond the thyroid capsule; T4a: solitary tumor, T4b: multifocal tumor
  • 68.
    • Regional Lymph Node Metastasis:
      • NX: Regional lymph node cannot be assessed
      • N0: No regional lymph node metastasis
      • N1: Regional lymph node metastasis;
    • N1a: ipsilateral lymph node metastasis
    • N1b: bilateral, midline, or contralateral cervical or mediastinal lymph node metastasis
  • 69.
    • Distant Metastasis:
      • MX: Distant metastasis cannot be assessed
      • M0: No distant metastasis
      • M1: Distant metastasis; specific metastatic sites (e.g. pulmonary (PUL), osseous (OSS), liver (HEP), brain (BRA), lymph nodes (LYM), etc)
    • Note : undifferentiated (anaplastic carcinoma) is considered by definition as stage IV tumors.
  • 70. Clinical staging of papillary or follicular carcinoma: Patient under 45 years of age
    • :
    • . Stage I: any T, any N, M0
    • . Stage II: any T, any N, M1
      • Patient over 45 years of age:
    • . Stage I: T1, N0, M0
    • . Stage II: T2 or T3, N0, M0
    • . Stage III: T4, N0, M0, or any T, N1, M0
    • . Stage IV: any T, any N, M1
  • 71.
    • Clinical staging of medullary carcinoma:
      • Stage I: T1, N0, M0
      • Stage II: T2, T3, or T4, N0, M0
      • Stage III: any T, N1, M0
      • Stage IV: any T, any N, M1
  • 72. Management
    • Well-differentiated Thyroid Carcinoma: (Papillary, Follicular, and Hurthle cell) Total thyroidectomy most commonly performed for WDTC. Total thyroidectomy allows for complete removal of primary tumor, reduced local recurrent rate to 26% (40% with lobectomy). Preparation for total thyroidectomy includes 131-I scanning, medication history, recurrent laryngeal nerve examination (pre-op documented recurrent laryngeal nerve function by Machida’s scope or direct laryngoscopy), and pre-op Tg level.
  • 73.
    • Partial thyroidectomy (lobectomy and isthmusectomy): is the basic minimal operation for thyroid cancers (nodulectomy is contraindicated). The procedure allows for identification and preservation of the parathyroid glands with blood supply and the recurrent laryngeal nerve. Indications for the procedure include unifocal, intrathyroidal, and nonmetastatic papillary carcinomas less than 1.0 cm in diameter; patient has no previous exposure to radiation and contralateral lobe is clinical normal.
  • 74.
    • Near total thyroidectomy leaves a minimal amount of thyroid tissue and preservation of the recurrent laryngeal nerve and parathyroid gland with their blood supply. This is the treatment for micro-carcinomas if multifocality or local lymph node metastasis is present. Micro-carcinomas are usually associated with bilateral tumor focci. Postoperative radioiodine scanning and therapy are necessary.
  • 75.
    • Role of neck dissection in conjunction with thyroidectomy for WDTC is a controversial topic. Several studies showed that pathological evaluation of elective neck dissection has not improved the survival rate in papillary carcinoma. No neck dissection is necessary for the N0 neck and there is wide agreement on this among head and neck surgeons.
  • 76.
      • patients age> 45, cervical lymph node positive, and positive mediastinal nodes need more aggressive treatment including modified neck dissection (preserves the jugular vein, SCM muscle, and spinal accessory nerve). Invasive tumors are removed completely with preservation of involved organs (trachea and esophagus). Elective removal of lymph node is inadequate and should be avoid.
  • 77. Adjuvant therapy
    • Post-op radioiodine (RAI): with appropriate dose, radiation therapy is safe in both children and adults. When patients have significant hypothyroidism (TSH>50 mU/L), 4 to 5 mCi of 131-I is given and the total body is scanned to look for residual thyroid tissue or metastasis. The scan and treatment are repeated until the scan is negative. Patient will receive follow up annually for several years.
  • 78. B. Undifferentiated Carcinoma
    •   These tumors are usually unresectable. Tracheotomy is considered when airway is compressed. Diagnosis is made by FNA and usually by open biopsy for completed cell study. A combination treatment of surgery, radiation or chemotherapy may help to control the tumors.
  • 79.
      • Chemotherapy: undifferentiated thyroid carcinoma is generally not chemotherapy-sensitive. The most effective agent is adriamycin (doxorubicin). The approved combination by FDA includes adriamycin and cisplatin with hyperfractionated radiotherapy and debulking surgery may be used.
  • 80.
      • Radiation therapy: anaplastic cancer does not concentrate 131-I. The only radiation is external beam therapy. Without evidence of apparent metastasis at the time of initial treatment, the average survival rate for this tumor is only 6 months.
    •  
  • 81. Medullary Thyroid Cancer:
    • Cervical metastasis at the time of diagnosis is observed in 50% of cases. Surgical resection includes the anterior compartment node dissection, which removes the lymphatics and adipose tissue from the hyoid bone to the sternal notch and laterally to the internal jugular vein. The lymph node groups removed are pre-tracheal, paratracheal, pre-cricoid, Delphian and perithyroidal nodes. With N(+) cervical lymph nodes, a selective lateral neck dissection of zones II, III, IV can be included.
  • 82.
    • The most effective treatment is primary total thyroidectomy. Indications include the following reasons: (1) the C-cells have diffuse and bilateral anatomic distribution resulting in multifocal and bilobular tumors, (2) in the sporadic form, 30% of patients have bilateral involvement, (3) in the family cases, bilateral involvement is 100%.

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