Schwartz,s principles of surgery 2005 presented by:.kamran

adhami M.D.

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.

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

• 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

• 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

• 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.

• 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

• 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.

• 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

• 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.

• 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

• 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.

• 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.

• 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.

• 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.

• 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.

• 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.

• 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.

• 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.

• 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.

• 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.

• 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

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

• 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.

• 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.

• 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).

• 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.

• 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.

• 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.

• 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.

• 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.

• 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

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.

• 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)

• 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

• 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

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

• 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

• 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.

• 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)

• 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

• 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

• 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

• 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%)

• 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.

• 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.

• 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.”

• 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.

• 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.

• 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.

• It usually present as solitary thyroid nodules,occasionally with a history of rapid size increase.and long-standing goiter.pain is uncommon,unless hemorrhage into the nodules has occurred.

• Cervical lymphadenopathy is uncommon at initial presentation(5%),although distant metastases may be present. In less than 1% of cases,follicular cancers may be hyperfunctioning,leading patients to present with signs and symptoms of thyrotoxicosis.

• FNA biopsy is unable to distinguish benign follicular lesions from follicular carcinomas.therefore,preoperative diagnosis of cancer is difficult unless distant metastases are present .large follicular tumors (>4cm)in older men are more likely to be malignant.

• Follicular carcinomas are usually solitary lesions,the majority of which are surrounded by a capsule.histologically ,folliclesare present,but the lumenmay be devoid of colloid.architectural patterns depend on the degree of differentiation demonstrated by the tumor. Malignancy is defined by the presence of capsular and vascular invasion.

• Minimally –invasive tumors appear grossly encapsulated but have evidence of microscopic invasion through the tumor capsule and/or invasion into small-to medium-size vessels (venous caliber)in or immediately outside the capsule,but not within the tumor.on the other hand,widely invasive tumors demonstrate evidence of large-vessel invasion and/or broad areas of tumor invasion through the capsule.

• They may,in fact,be unencapsulated .it is important to note that there is a wide variation of opinion among clinicians and pathologists with respect to the above definitions. Tumor infiltration and invasion ,as well as tumor thrombus within the middle thyroid or jugular veins,may be apparent at operation.

• Patients diagnosed by FNA B as having a follicular lesion should undergo thyroid lobectomy because at least 80%of these patients will have benign adenomas.some surgeons recommened total thyroidectomy in older patients with follicular lesions larger than 4 cm because of the higher risk of cancer in this setting(50%).

• Intraoperative frozen-section examination usually is not helpful, but should be performed when there is evidence of capsular or vascular invasion,or when adjacent lymphadenopathy is present. Total thyroidectomy should be performed when thyroid cancer is diagnosed. There is debate among experts about whether patients with minimally –invasive follicular cancers should undergo completion thyroidectomy because the prognosis is so good in these patients.

• A diagnosis of frankly invasive carcinoma necessitates completion of total thyroidectomy primarily so that I can used to detect and ablate metastatic disease. Total thyroidectomy in patients with angioinvasion is also recommended.prophylactic nodal dissection is unwarranted because nodal involvement is infrequent,but in the unusual patient with nodal metastases,therapeutic neck dissection is recommended.

• The cumulative mortality from follicular thyroid cancer is 15% at 10years and 30% at 20 years. poor long-term prognosis is predicted by age older than 50 years at presentation ,tumor size larger than 4 cm ,higher tumor grade,marked vascular invasion,extrathyroiad invasion,and distant metastases at the time of diagnosis.

• Account for 3% of all thyroid malignancies. Under the world health organization classification ,hurthle cell carcinomas are considered to be a subtype of follicular thyroid cancer.like follicular cancers,hurthle cell cancers are characterized by vascular or capsular invasion,and therefore cannot be diagnosed by FNA B.tumors contain sheets of eosinophilic cells packed with mitochondria ,which are derived from the oxyphilic cells of the thyroid .gland.

• Hurthle cell tumors also differ from follicular carcinomas in that they are more often multifocal and bilateral(30%) usually do not take up RAI (5%),are more likely to metastasize to local nodes (25%)and distant sites,and are associated with a higher mortality rate(20% at 10 years). Hence,they are considered to be a separate class of tumors by some surgeons.

• Management is similar to that of follicular neoplasms,with lobectomy and isthmusectomy being sufficient surgical treatment for unilateral hurthle cell adenomas.

• When hurthle cell neoplasms are found to be invasive on intraoperative,frozen-section,or definitive paraffin-section histology,then total thyroidectomy should be performed.

• These patients should also undergo routine central neck node removal,similar or patients with MTC,and modified radical neck dissection when lateral neck nodes are palpable.

• Although RAI scanning and ablation usually are ineffective ,they probably should be considered for ablation of any residual normal thyroid tissue and,occasionally ,for ablation of tumors,because there is no other good therapy.

• Thyroxine is necessary not only as replacement therapy in patients after total or near total thyroidectomy but has the additional effect of suppressing TSH and reducing the growth stimulus for any possible residual thyroid cancer cells.

• TSH suppression reduce tumor recurrence rates,particularly in young patients with papillary and follicular thyroid cancer.

• Thyroxine should be administered to ensure that the patient remains euthyroid,with circulating TSH levels at about 0.1uU/L in low risk patients,or less than 0.1uU/mL in high-risk patients.

• The risk of tumor recurrence must be balanced with the side effects associated with prolonged TSH suppression,including osteopenia and cardiac problems,particularly in older patients.

• Thyroglobulin levels in patients who have undergone total thyroidectomy should be below 2ng/ml when the patient is taking T4,and below5ng/ml when the patient is hypothyroid. a Tg level above 2 ng/ml is highly suggestive of metastatic disease or persistent normal thyroid tissue,especially if it increases when TSH levels increase when the patient is hypothyroid during preparation for RAI scanning.

• 95% of patients with persistent or recurrent thyroid cancer of follicular cell origin will have Tg levels higher than 2ng/ml. thyroglobulin and anti-Tg antibody levels should be measured initially at 6month intervals and then annually if the patient is clinically disease free.

• The issue of whether RAI therapy offers any benefit to patients with differentiated thyroid cancer remains controversial in the absence of prospective,randomized controlled trials.some experts advise routine RAI scan and therapy for all patients except those with occult or minimally –invasive tumors,whereas others only high-risk patients.

• If RAI scan are negative ,but Tg levels remain elevated,other imaging studies such as neck ultrasound,MRI,and FDG-PET scan may be considered.

• MTCs acoount for about5% of thyroid malignancies and arise from the parafollicular or C cells of the thyroid,which,in turn,and derived from the ultimobranchial bodies. These cells are concentrated superolaterally in the thyroid lobes,which is where MTC usually develops.

• C cell secrete calcitonin,a 32-amino-acid polypeptide that functions to lower serum calcium levels. In some animals,especially those that lay eggs with shells,calcitonin is a significant regulator of calcium metabolism,but in humans,it has only minimal physiologic effects.

• Most of MTC occur sporadically,however,25% occur within the spectrum of several inherited syndromes such as familial medullary thyroid cancer,MEN2A,and MEN2B.all these variants are known to result secondary to germline mutations in the RET proto-oncogene.

• The syndromes are also characterized by genotype-phenotype correlations,with specific mutations leading to particular clinical manifestations.

• Patients with MTC often present with a neck mass that may be associated with palpable cervical lymphadenopathy (15 to 20%). local pain or aching is more common in patients with these tumors,and local invasion may produce symptoms of dysphagia,dyspnea,or dysphonia.

• Distant blood-borne metastases to the liver ,bone(osteoblastic),and lung occur later in the disease.the f:m ratio 1.5:1. most patients present between 50 and 60 y.o. of age.although patients with familial disease present at a younger age.

• Medullary thyroid tumors secrete not only calcitonin and carcinoembryonic antigen(CEA),but also other peptides such as calcitonin gene-related peptide(CGRP),histaminadases,prostaglandins E2 &F2,and serotonin. Patients with extensive metastatic disease frequently develop diarrhea ,which may result from increased intestinal motility and impaired intestinal water and electrolyte flux.

• MTCs are typically unilateral(80%)in patients with sporadic disease,and multicentric in familial cases,with bilateral tumors occuring in up to 90% of familial patients.

• Microscopically ,tumors are composed of sheets of infiltrating neoplastic cells separated by collagen and amyloid.marked heterogeneity is present;cells may be polygonal or spindle-shaped.

• The diagnosis of MTC is established by history, physical examination,raised serum calcitonin or CEA levels,and FNA cytology of the thyroid mass. Attention of family history is important because approximately 25% of patients with MTC have familial disease.

• Because it is not possible to distinguish sporadic from familial disease at initial presentation,all new patients with MTC should be screened for RET point mutations,pheochromocytoma(24-hour urinary levels of VMA,catecholamine,and metanephrine),and hyperparathyroidism (serum calcium).

• It is important to rule out a coexisting pheochromocytoma to avoid precipitating a hypertensive crisis and death.

• If patients are found to have a pheochromocytoma,this must be operated on first. these tumors are generally bilateral(50%). Total thyroidectomy is the treatment of choice for patients with MTC because of the high incidence of muticentricity,the more aggressive course,and I therapy is not usually effective.

• The central compartment nodes are frequently involved early in the disease process ,so that a bilateral central neck node dissection should be routinely performed. in patients with palpable cervical nodes or involved central neck nodes,ipsilateral or bilateral ,modified radical neck dissection is recommended.

• Similarly, patients with tumors larger than 1.5 cm should undergo ipsilateral prophylactic modified radical neck dissection,because greater than 60% of these patients have nodal metastases.30% of these patients will also have contralateral nodal metastases.

• In the case of locally recurrent or metastatic disease,tumor debulking is advised,not only to ameliorate symptoms of flushing and diarrhea,but also to decrease risk of death from recurrent central neck or mediastinal disease.

• Total thyroidectomy is indicated in RET mutation carries once the mutation is confirmed.the procedure should be performed before age6 years in MEN2 patients and prior to age 1 year in MEN2B patients.

• Prognosis is related to disease stage.the10-year survival rate is 80% but decrease to 45% in patients with lymph node involvement.survival also is significantly influenced by disease type. It is best in patients with non-MEN familial MTC,followed by patients with MEN2A,and then by patients with sporadic disease.and is worst in whom with MEN2B(35%in 10 y)

• It accounts for 1%of all thyroid malignancies in the u.s. and is declining in incidence.women are more commonly affected.and the majority of tumors present in the seven and eighth decades of life.the typical patient has a long-standing neck mass,which rapidly enlarges and may be painful.

• Associated symptoms,such as dysphonia ,dysphagia,and dyspnea,are common.the tumor is large and may be fixed to surrounding structures or may be ulcerated. Lymph nodes usually are palpable at presentation.

• On gross inspection,anaplastic tumors are firm and whitish in appearance.microscopically,sheets of cells with marked heterogeneity are seen.cells may be spindle-shaped,polygonal or large,multinucleated cells.

• This tumor is one of the most aggressive thyroid malignancies,with few patient surviving 6 months beyond diagnosis. All forms of treatment have been disappointing .if anaplastic carcinoma presents as a resectable mass,thyroidectomy may lead to a small improvement in survival,espicially in younger individuals.

• Combined radiation and chemotherapy in an adjuvant setting in patients with resectable disease has been associated with prolonged survival.tracheostomy may be needed to alleviate airway obstruction.

• Lymphomas account for less than 1% of thyroid malignancies and most are of the non-Hodgkin,s B-cell type.although the disease can arise as part of a generallized lymphomatous condition,most thyroid lymphomas develop in patients with chronic lymphocytic thyroiditis.

• Patients usually present with symptoms similar to those of patients with anaplastic carcinoma,although the rapidly enlarging neck mass often is painless.patients may present with acute respiratory distress. The diagnosis usually is suggested by FNA biopsy.although needle-core or open biopsy may be necessary for definitive diagnosis.

• they respond rapidly to chemotherapy which is also associated with improved survival .combined treatment with radiotherapy and chemotherapy is often recommended.thyroidectomy and nodal resection are used to alleviate symptoms of airway obstruction in patients who do not respond quickly to the above regimens,or in patients who have completed the regimen prior to diagnosis.

• The overall5-y survival rate is about 50%;

• Thyroid is a rare place for metastases from other cancers include:kidney,breast ,lung and melanoma physical exam.and history often identified the source of metastases. And FNAB gives the defenitive diagnosis.in most of patients according to primary tumor,lobectomy may be helpful.