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solitary thyroid nodule

solitary thyroid nodule. Schwartz,s principles of surgery 2005 presented by:.kamran adhami M.D.

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solitary thyroid nodule

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  1. solitary thyroid nodule Schwartz,s principles of surgery 2005 presented by:.kamran adhami M.D.

  2. Present in 4% of individuals in u.s.a thyroid cancer has much lower incidence of 40new case per 1 million majority of thyroid nodules are benign and don’t require removal.

  3. history Time of onset-change in size-associated symptoms such as pain,dysphagia,dyspnea,choking *pain is an unusual symptom=hemorrhage in a benign nodule,thyroiditis,malignancy *medullary cancer complain of a dull aching sensation *hoarseness is worrisome because it may be secondary to malignant involvement of the recurrent laryngeal nerves

  4. Most importantly,patients should be questioned regarding risk factors for malignancy,such as exposure to ionizing radiation and family history of thyroid and other malignancies associated with thyroid cancer

  5. external beam radiation • Low dose therapeutic radiation has been used to treat conditions such as tinea capitis,thymic enlargement,enlarged tonsils & adenoids,acne volgaris and other conditions such as hemangioma and scrofula..and integral part of the management of hodgkin,s disease. It is now known that a history of exposure to low dose ionizing radiation to the thyroid gland place the patient at increase risk for thyroid cancer

  6. Increases linearly from 6.5 to 2000 cGy,beyond which the incidence declines as the radiation causes destruction of tissue. after 20-30 y the risk is max.

  7. Most thyroid carcinomas following radiation exposure are papillary-solid type RET/PTC translocation. More aggressive,local invasion,multifocality,lymph node metastases,higher stage at presentation

  8. family history • Family history is a risk factor for development of both medullary and nonmedullary thyroid cancer. Familial medullary cancers occur in isolation or in association with other tumors as part of multiple endocrine neoplasia type2(MEN2) syndromes. Nonmedullary thyroid cancer can occur in association with other familial cancer syndroms such as:werner,FAP,COWDEN,S.

  9. COWDEN=intestinal hamartomas,benign and malignant breast tumors,follicular thyroid cancer,papillary thyroid cancer, hurthle cell tumors FAP=colon polyps and cancer,duodenal neoplasms,desmoids,papillary thyroid cancer WERNER=adult progeroid syndrome,papillary thyroid cancer,follicular thyroid cancer,anaplastic cancer

  10. physical examination • Move with swallowing . Gland is best palpated from behind the patient and with the neck in mild extension. cricoid cartilage is an important landmark,isthmus is situated just below it. Nodules that are hard,gritty,or fixed to surrounding structures,such as to the trachea or strap muscles are more likely to be malignant. Cervical chain of lymph nodes-posterior triangle. Delphian node and pyramidal lobe situated just above the isthmus.

  11. diagnostic tests • Solitary thyroid nodule=FNAB 1-nondiagnostic=repeat FNAB 2-benign:A;cyst=aspirate=reaccumulates#3=thyroidectomy B:colloid nodule=observe considerT4therapy=continued growth compressive symptoms=(FNAB+-)thyroidectomy 3-suspicious,folicular lesion=RAI scan:A-HOT=thyroidectomy or RAI,B-COLD=thyroidectomy 4-malignant=thyroidectomy

  12. fine-needle aspiration biopsy • Most important test+-ultrasound ultrasound is recommended for nodules that are difficult to palpate and for complex solid cystic nodules that recur after the initial aspiration. 23gauge needle.immediately placed on dry glass slides.70%alcohol solution, others are air dried.papanicolaou or wright if a bloody aspirate is obtained,patient should be repositioned in a more upright position and repeated with a finer25 to 30 needle.

  13. Afer biopsy,categorized into following groups: benign(65%),suspicious(20%),malignant(5%),nondiagnostic(10%) false-positive is 1%,false-negative 3% nondiagnostic=usually be repeated bloody FNA may also be reported as nondiagnostic and often indicates a follicular neoplasm. Benign lesions=cysts,,colloid nodules.(<3%) risk of malignancy in suspicious=10-20%(follicular or hurthle cell neoplasm)diagnosis of malignancy relies on demonstrating capsular or vascular invasion that cannot be determined via FNA.

  14. FNA biopsy is also less reliable in who have a history of head and neck irradiation or a family history of thyroid cancer,because of a higher likelihood of multifocal lesions.

  15. laboratory studies • Most patients are euthyroid. TSH is helpful. hyperthyroid=risk of malignancy is1% level of Tg cannot differentiate benign from malignant nodules unless the levels are extremely high-metastatic thyroid cancer should be suspected.

  16. thyroglobulin levels are usful in following patients who undergone total thyroidectomy for cancer,or for who follow for serial evaluation for non operative management of thyroid nodules.

  17. Serum calcitonin levels should be obtained in patients with medullary cancer of a family history of MTC or MEN2 RET oncogene mutations and have a 24 h urine collection with measurment of levels of vanillylamandelic acid ,metanephrine,and catecholamine to rule out a pheochromocytoma.

  18. Ultrasound is helpful for nonpalpable thyroid nodules.(solid from cystic) and for identifying adjacent lymphadenopathy. Size of suspected benign nodules diagnosed by FNAB. CT.MRI,are unnecessary in routine evaluation.exept for large,fixed,or substernal lesions. imaging

  19. Scanning the thyroid with I123 or I 99 Tc is rarely necessary,unless for hot or automonous thyroid nodules.thyroid scanning is recommended in thyroid nodules in who have follicular thyroid nodules on FNA and a suppressed TSH.

  20. MANAGEMENT • Simple thyroid cysts resolve with aspiration in 75% of cases. some require a second or third aspiration.if it persists after three attempts at aspiration,unilateral thyroid lobectomy is recommended. lobectomy is also recommended for cysts greater than 4 cm in diameter and for complex cysts with solid and cystic components.

  21. When FNA is used in complex nodules,the solid portion should be sampled. A colloid nodule in biopsy,patient should be observed with serial ultrasound and Tg measurements.if it enlarges,repeat FNA is often indicated.and L-thyroxine in doses sufficient to maintain a serum TSH level between 0.1 and 1 u/ml may also be administered.

  22. 50%of these nodules decrease in size in response to TSH supression of this regimen,and others may not continue to grow,but is effective for smaller than 3cm. Suppression of TSH increase the risk of osteoporosis and cardiac arrhythmias. If a nodule enlarges on TSH suppression,causes compressive symptoms,or for cosmetic reason=thyroidectomy but in patient who had previous irradiation of the thyroid or who has a family history of cancer,total or near total thyroidectomy is recommended

  23. malignant thyroid disease • In usa thyroid cancer is less than 1% of malignancies(2%f-0.5%m) 6 deaths per 1 million persons annually.

  24. papillary carcinoma • 80% of all thyroid malignancies in iodine-sufficient areas and is the predominant cancer in children and individuals exposed to external radiation. Occurs more often in women with a 2:1 f:m ratio;mean age is 30 to 40 y. Most are euthyroid and present with a slow-growing painless mass in the neck.

  25. Dysphagia,dyspnea,and dysphonia are usually associated with locally advanced invasive disease.lymph node metastases are common,especially in children and young adults,and may be the presenting complaint.

  26. pathology • On gross examination ,PTCs are generally hard and remain flat on sectioning with a blade,in contrast to normal tissue or benign nodular lesions that tend to bulge. Histologically,papillary carcinomas may exhibit papillary projections. A mixed pattern of papillary and follicular structures,or a pure follicular pattern.(follicular variant).

  27. The diagnosis is established by characteristic celluar features. Cells are cuboidal with pale,abundant cytoplasm,grooving,crowded nuclei,and intranuclear cytoplasm inclusions,leading to the designation of orphan annie nuclei, which allows diagnosis by FNAB.psammoma bodies,which are microscopic,calcified deposits representing clumps of sloughed cells,may be present.

  28. Mixed papillary-follicular tumors and follicular variant of papillary carcinoma are classified as papillary carcinomas because they act biologically as papillary carcinomas.multifocality is common in papillary carcinoma and may be present in up to 85% of cases on microscopic examination.

  29. Multifocality is associated with an increased risk of cervical nodal metastases and these tumors may rarely invade adjacent structures such as the trachea,esophagus,and recurrent laryngeal nerves.

  30. Macroscopically, there are three recognized forms of PTC,each based on the size and extent of the primary disease. Minimal or occult/microcarcinoma tumors originally included papillary cancers up to 1.5 cm in diameter.they now are defined as tumors of 1 cm or less in size with no evidence of local invasiveness throug the thyroid capsule or angioinvasion,and are not associated with lymph node metastases.

  31. They are nonpalpable and usually are incidental findings at operative,histologic,or autopsy examination.occult papillary thyroid cancer is present in 2 to 36%of throid glands removed at autopsy.the recurrence rate in patients with tumors 1.5cm or smaller after removal is 5%and the mortality rate 0.5%. Long term prognosis is better for patients with intrathyroidal lesions.

  32. prognostic indicators • In general ,patients with PTC have an excellent prognosis with a greater than95% 10-year survival rate. In1987 hay and associates,proposed the AGES scoring system which incorporates age,histologic grade,extrathyroidal invasion,and metastases and tumor size to predict the risk of dying from papillary cancer.low risk patient are young,with well differentiated tumors,no metastases,and small primary lesions,whereas high risk are older,poorly differentiated tumors local invasions,distant metastases and large primary lesion

  33. The MACIS scale is a more sophisticated postoperative system modified from the AGES scale.this scale incorporates distant metastases,age at presentation,completeness of original surgical resection,extrathyroidal invasion,and size of original lesion and classifies patients into four risk-groups based on their scores.

  34. Another classification system is the TNM system.(tumor,nodal status,metastases)used by most medical centers in north america. degroot and associates uses four groups:class1(intrathyroidal)class2(cervical nodal metastases)class3(extrathyroidal invasion)and class4(distant metastases)

  35. Papillary or follicular tumors: younger than age 45 years 1=any t,any n,m0 2=any t,any m,m1 age 45 and older 1=T1N0M0 2=T2N0M0 3=T3N0M0,T1-3,N1aM0 4A=T4aN0-1aM0,T1-4aN1bM0 4B=T4b,anyN,M1 4C=anyT,anyN,M1

  36. MEDULLARY THYROID CANCER: 1=T1N0M0 2=T2-3N0M0 3=T1-3N1aM0 4A=T4aN0-1a,M0,T1-4a,N1b,M0 4B=T4b,anyN,M0 4C=any T,anyn,M1

  37. ANAPLASTIC CANCER: 4A=T4a,anyN,M0 4B=T4b,anyNM0 4C=anyT,anyN,M1

  38. surgical treatment • Patients with highrisk tumors(judged by any of the classification systems discussed before)or bilateral tumors should undergo total or near total thyroidectomy. when patients have a minimal papillary thyroid carcinoma in a thyroid specimen removed for other reason,unilateral thyroid lobectomy and isthmusectomy is considered to be adequate treatment,unless the tumor has evidence of angioinvasion,multifocallity,or positive margins

  39. The optimal surgical strategy in the majority of patients with lowrisk cancers remains contraversial-the focus of the debate centers around outcome data and risks associated with either lobectomy or total thyroidectomy in this group.

  40. Proponents of total thyroidectomy argue that the procedure 1-enables one to use RAI to effectively detect and treat residual thyroid tissue or metastatic disease 2-makes the serum Tg level a more sensitive marker of recurrent or persistent 3-eliminates the contralateral occult cancers as site of recurrence(85%multifocal)

  41. 4-reduces the risk of recurrence and improves survival 5-decreases the 1% risk of progression to undifferentiated or anaplastic thyroid cancer 6-reduce the need for reoperative surgery with its attendant risk of increased complication rates

  42. Investigators that favor lobectomy argue that: 1-total thyroidectomy is associated with a higher complication rate than lobectomy 2-recurrence in the remaining thyroid tissue is unusual(5%)and most are curable by surgery 3- tumor multicentricity seems to have little prognostic significance 4-patients who have undergone lesser procedures such as lobectomy still have an excellent prognosis

  43. A significant proportion (33to50%) of patients who develop a recurrence die from their disease,and even though the data are retrospective, long term followup studies suggest that recurrence rates are lowered, and some but not all,investigations suggest that survival is improved in patients undergoing near total or total thyroidectomy

  44. Diminished survival is noted in patients with so called lowrisk disease(mortality rate of 5% at10to20 years)and its not possible to accurately risk stratify patients preoperatively. Given the above,it is recommended that even patients with low-risk tumors undergo total or neartotal thyroidectomy,provided complication rates are low(<2%)

  45. Consequently,most patients with thyroid nodules should have FNA biopsy performed. When PTC is diagnosed,the definitive operation can be done without confirming the diagnosis by frozen section during the operation. patients with a nodule that may be papillary cancer should be treated by thyroid lobectomy,isthmusectomy,and removal of any pyramidal lobe or adjacent lymph nodes.

  46. If intraoperative frozen-section examination of a lymph node or of the primary tumor confirms carcinoma,completion of total or near total thyroidectomy should be performed.if a de dfinitive diagnosis cannot be made,or if the surgeon is concerned about the viability of the parathyroid glands or the status of the RNL,the operation should be terminated.

  47. During thyroidectomy,enlarged ipsilateral central neck nodes should be removed.lymph node metastases in the lateral neck in patients with papillary carcinoma usually should be managed with modified radical or functional neck dissection as described later under”neck dissection for nodal metastases.”

  48. Dissection of the posterior triangle and suprahyoid dissection are usually not necessary unless there is extensive metastatic disease in level 2,3,and4 but should be performed when appropriate.

  49. Prophylactic neck node dissection is not necessary in patients with PTC because these cancers donot appear to metastasize systemically from lymph nodes and micrometastases appear to be ablated with RAI therapy.

  50. follicular carcinoma • Follicular carcinomas account for 10% of thyroid cancers and occur more commonly in iodine-deficient areas. The overall incidence of this tumor is decli ning in the u.a. probably as a result of iodine supplementation and improved histologic classification. Women have a higher incidence of that with a f:m ratio 3:1 and a mean age of 50 y.

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