378 Thyroid Nodules Flashcards

1
Q

Weight of thyroid gland

A

12-20 grams

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2
Q

Drugs that prevent the peripheral conversion of thyroid hormones

A

PTU
Propranolol
Glucocorticoids
Amiodarone

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3
Q

Half life of T3

A

2 days

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4
Q

True or false. Right lobe of thyroid is larger than the left

A

True

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5
Q

Percentage of T4 coming from the thyroid

A

100%

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6
Q

Percentage of T3 coming from thyroid

A

20%

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7
Q

RAI contraindication

A

Pregnancy

Breastfeeding

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8
Q

When does thyroid synthesis begin

A

11 weeks gestation

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9
Q

Where does the thyroid gland develop

A

Floor of the primitive pharynx during 3rd week of gestation

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10
Q

Failure of the thyroid gland to migrate in the neck and is found at the base of the tongue

A

Lingual thyroid

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11
Q

Gives rise to calcitonin

A

Thyroid medullary C cells

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12
Q

Where are the C cells located

A

Upper 1/3
Lower 2/3
Of thyroid gland

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13
Q

Orchestrate thyroid gland development

A

Homeobox-8 (PAX 8)

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14
Q

Where are the follicular cells of the thyroid located

A

Basolateral surface

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15
Q

Subunit of TSH common to other hormones and the subunit unique to TSH

A

Alpha unit similar to other glycoprotein hormones

Beta unit unique to TSH

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16
Q

What hormones are similar to the TSH alpha unit

A

LH
FSH
hCG

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17
Q

Suppresses TSH

A

Dopamine
Glucocorticoids
Somastostatin

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18
Q

Major positive regulator of TSH

A

TRH

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19
Q

Critical first step in thyroid hormone synthesis

A

Iodine uptake

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20
Q

Mediated iodide uptake, expressed in the basolateral membrane of the follicular cells

A

NIS (Sodium iodide symporter)

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21
Q

Low levels of NIS is expressed in which organs

A

Salivary glands
Lactating breast
Placenta

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22
Q

Iodine transporter in the basolateral surface? On the apical surface?

A

Basolateral: NIS
Apical: pendrin

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23
Q

Disorder characterized by defective organification of iodine, Goiter had sensorinueral deafness

A

Pendred syndrome

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24
Q

Characterized by mental and growth retardation in iodine deficient regions

A

Cretinism

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25
Q

Concomitant deficiency in cretinism that contribute to neurologic manifestation

A

Selenium deficiency

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26
Q

Recommended average daily intake of iodine

A

150-250 ug/day

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27
Q

Disorders of thyroid hormone synthesis is due to what mutations

A

Recessive mutations of TPO or Tg

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28
Q

Excess iodide transiently inhibits thyroid iodide organification

A

Wolf chaikoff phenomenon

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29
Q

Types of deiodinases. Where are they found

A

Type I: low affinity, thyroid, liver and kidneys
Type II: strong affinity, pituitary, brain, brown fat, thyroid
Type III: most import source of rT3

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30
Q

Caused by self administration of thyroid hormone

A

Thyrotoxicosis factitia

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31
Q

Increased in all type of Thyrotoxicosis except Thyrotoxicosis factitia

A

Serum Tg

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32
Q

Main role of Tg measurement

A

Follow up thyroid cancer

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33
Q

Hot vs cold nodule on thyroid scintigraphy

A

Hot: never malignant
Cold: likely malignant

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34
Q

Most common type of thyroid cancer

A

Papillary thyroid cancer

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35
Q

Characteristic cytologic features of PTC

A

psammoma bodes, cleaved nuclei with orphan annie appearance

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36
Q

Where does follicular thyroid cancer spread?

A

hematogenously to bone, lung, and CNS

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37
Q

Main stay of thyroid cancer treatment as most tumors are TSH responsive

A

levothyroxine suppression

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38
Q

Aggressive thyroid cancer and patient often die 6 months of diagnosis

A

anaplastic thyrpid cancer

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39
Q

True or false. lymphoma in the thyroid gland often arises in the background of Hashimotos thyroiditis

A

True

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40
Q

Most common type of thyroid lymphoma

A

Diffuse large cell lymphoma

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41
Q

refers to an enlarged thyroid gland

A

goiter

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42
Q

True or false. Graves’ disease and Hashimoto’s thyroidism are also associated with goiter

A

True.

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43
Q

pathogenesis of goiter in Grave’s disease

A

TRH mediated effects of thryoid stimulating immunoglobulin

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44
Q

pathogenesis of goiter in Hashimoto’s thyroidism

A

goitrous form pccurs because of acquired defects in hormone synthesis, leading to elevated levels of TSH and its consequent growth effects

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45
Q

Diffuse enlargement of the thyroid in the absence of nodules and hyperthyroidism

A

diffuse nontoxic goiter

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46
Q

other name of diffuse nontoxic goiter

A

simple goiter, colloid goiter

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47
Q

most common cause of diffuse goiter worldwide

A

iodine deficiency

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48
Q

thyroid enlargement in teenagers

A

juvenile goiter

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49
Q

true or false. In iodine deficient areas, thyroid enlargement reflects a compensatory effort to trap iodine and produce sufficient hormone when hormone synthesis is relatively inefficient

A

True.

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50
Q

what is the action of iodine to thyroid growth

A

direct actions on thyroid vasculature and indirectly affect growth through vasoactive substances such as endothelin and nitric oxide

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51
Q

abnormal thyroid volume on ultrasound

A

more than 30 ml

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52
Q

refers to the facial and neck congestion due to jugular venous obstruction when the arms are raised above the head

A

Compression exceed 70% of the tracheal diameter

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53
Q

manuever that draw the thyroid to the thoracic inlet

A

Pembertons sign

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54
Q

associated with Pemberton signs

A

substernal goiter

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55
Q

laboratory findings that support iodine deficiency

A

low urinary iodine levels less than 50 ug/L

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56
Q

True or false. Iodine replacement induces variable regression of goiter in iodine deficiency depending on the duration and degree of hyperplasia

A

True.

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57
Q

conditions where surgery is indicated in diffuse goiter

A

tracheal compression or obstruction of the thoracic inlet

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58
Q

True or false. Surgery is rarely indicated for diffuse goiter

A

True.

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59
Q

True or false. TSH is play an permissive or contributory role in nontoxic multinodular goiter

A

True.

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60
Q

True or false. Most patients with nontonic multinodular goiter are asymptomatic and euthyroid

A

True.

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61
Q

What leads to hoarseness of voice in patient with goiter

A

laryngeal nerve involvement

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62
Q

True or false. Pain and hoarseness of voice in goiter suggests malignancy

A

True.

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63
Q

At what level can tracheal compression lead to significant airway compromise

A

Compression exceed 70% of the tracheal diameter

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64
Q

sonographic features assocaited with thyroid cancer

A

hypoechoic compared with surrounding thyroid, marked hypoechogenicity, microcalcifications, irregular microlobulated margins, solid consistency, taller than wide shape on transverse view

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65
Q

characterized by enhanced thyroid production by autonomous nodules

A

Jod Baselow effect

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66
Q

can be used when surgery is contraindicated in areas where large nodular goiter are more prevalent

A

radioiodine

67
Q

action of radioiodine in toxic nultinodular goiter

A

decrease MNG volume and may selectively ablate regions of autonomy

68
Q

usual dosage of 131I

A

3.7 Mbq (0.1 mCi) per gram of tissue, corrected for uptake 370- 1070 Mbq (10-29 mCi)

69
Q

administered concomitantly with 131I to increase effectiveness

A

TSH 0.1 mg IM

70
Q

True or false. Spontaneous remission on toxic multinodular goiter does not occurs as compared to Graves disease so treatment is lifelong

A

True.

71
Q

treatment of choice for toxic multinodular goiter

A

radioiodine

72
Q

solitary autonomously functioning thyroid nodule

A

toxic adenoma

73
Q

pathogenesis of toxic adenoma

A

mutations in the TSH-R

74
Q

less common mutations seen in toxic adenoma

A

Gsa mutations

75
Q

activating mutations identified in more than 90% of patients with toxic adenoma

A

active mutations in the TSH-R or Gsa

76
Q

in hyperfunctioning solitary nodule, when is thyrotoxicosis generally detected

A

when nodule is more than 3 cm

77
Q

provides definitive diagnostic test for hyperfunctioning solitary nodule

A

thyroid scan

78
Q

treatment of choice for hyperfunctioning solitary nodule

A

radioiodine ablation

79
Q

True or false. In hyperfunctioning thryoid nodule, medical therapy with antithyroid drug and beta blocker can normalize thyroid function but is not optimal long term treatment

A

True.

80
Q

adenoma composed of oncocytic follicular cells arranaged in follicular pattern

A

Hurthle cell adenoma

81
Q

can follicular carcinoma be diagosed by FNA

A

microcystic areas comprise more than 50% of the nodule volume

82
Q

diagnostic procedure of choice to evaluate thyroid nodules

A

FNA with ultrasound guidance

83
Q

when should levothyroxine therapy be discontinue in thyroid nodule

A

no decrease in size after 6-12 months of therapy

84
Q

what is the target TSH when giving levothyroxine in patients with thyroid nodule

A

TSH should be maintaiend just the lower limit of normal

85
Q

most common malignancy of endocrine system

A

thyroid cancer

86
Q

thyroid cancer with good prognosis

A

papillary thyroid cancer and follicular thyroid cancer

87
Q

thyroid cancer associated with a bleak progosis

A

anaplastic thyroid cancer

88
Q

True or false. Thyroid cancer is twice as common in women as men but male gender is associated with worse prognosis

A

True.

89
Q

risk factors for thyroid carcinoma in patients with thyroid nodule

A

history of head or neck irradiation, exposure to ionizing radiation from fallout, age less than 25 or more than 65, rapidly enlarging neck mass, male gender, family history, vocal cord paralysis, hoarseness of voice, nodule fixed to adjacent structures, lateral cervical lymphadenopathy

90
Q

True or false. Anaplastic thyroid cancer has only one stage, Stage IV

A

True.

91
Q

True.

A

more than 4 cm or with tumor extention

92
Q

more than 4 cm or with tumor extention

A

T1a less than 1 cm, T1b more than 1 cm but less than 2 cm

93
Q

T2 in thyroid cancer

A

More than 2 cm but not more 4 cm

94
Q

True or false. Higher TSH levels are associated with increased thyroid cancer risk

A

True.

95
Q

mutations relatively specific for thyroid neoplasm

A

RET/PTC, PAX8-PPAR gamma 1

96
Q

mutations associated with loss of iodine uptake by tumor celle

A

BRAF V600E

97
Q

Most common type of thyroid cancer

A

papillary thyroid carcinoma

98
Q

associated with large clear nuclei with powdery chromatin with nuclear grooves and prominent nucleoli

A

orphan Annie eyes in PTC

99
Q

thyroid cancer more common in iodine deficient regions

A

follicular thyroid cancer

100
Q

Can follicular carcinoma be diagosed by FNA

A

No

101
Q

Why cant FTC be diagnosed on FNA

A

distinction between benign and malignant follicular cells require histology as nuclear features of follicular adenoma and carcinomas do not differ

102
Q

differentiate follicular carcinoma from adenoma

A

in carcinoma, there is presence of capsular or vascular invasion

103
Q

Spread of PTC

A

lymphatics but also hematogenously

104
Q

Spread of FTC

A

hematogenous

105
Q

initial surgical procedure for thyroid cancer more than 1 cm but less than 4 cm

A

unilateral (lobectomy) or bilateral (near total thyroidectomy)

106
Q

unilateral (lobectomy) or bilateral (near total thyroidectomy)

A

bilateral surgery and radioiodine for remnant ablation

107
Q

True or false. Most thyroid tumor are TSH responsive

A

True.

108
Q

Mainstay of thyroid cancer treatment

A

levothryoxine suppresion of TSH

109
Q

TSH level for those with known metastatic disease

A

TSH less than 0.1 mIU/L

110
Q

TSH level for low risk of recurrence

A

lower normal limit 0.5-2.0 mIU/L

111
Q

TSH level for intermediate risk for recurrence

A

0.1-0.5 mIU/L

112
Q

TSH level for high risk for recurrence

A

less than 0.1 mIU/L

113
Q

what is the TSH level at the time of 131I therapy

A

more than 25 mIU

114
Q

Strategy of remnant ablation

A

one is treat patient with liothyronine 25 ug OD or BID for several weeks then hormone withdrawal for 2 week; Two is administration of recombinant human TSH (rhTSH) as two daily consecutive injections of 09 mg with administration of 131I about 24 hours after the second injection

115
Q

sensitive marker of residual/ recurrent thyroid cancer after ablation of the residual postsurgical thryoid tissue

A

serum thyroglobulin

116
Q

Where is the common recurrence of PTC

A

cervical lymph nodes

117
Q

what should be performed post ablation in PTC

A

neck ultrasound 6 months after thyroid ablation

118
Q

True or false. ATC has poor prognosis and most patients die within 6 months of diagnosis

A

True.

119
Q

True or false. Neck ultrasound is more sensitive than whole body scan in detecting recurrences of PTC in cervical lymph nodes

A

True.

120
Q

what is the risk of structural recurrence for no clinical evidence of residual disease after ablation, negative cervical sonography, and basal Tg less than 0.2 mg/ml on levothyroxine

A

less than 3% at 5 years

121
Q

what is the Tg level to get 3% recurrence at 5 years

A

Tg less than 0.2 mg/ml

122
Q

True or false. In ATC due to undifferentiated state of these tumors, the uptake of radioiodine is usually negligible

A

True.

123
Q

Lymphoma in the thryoid gland often arise in the background of what thyroiditis

A

Hashimoto’s thyroiditis

124
Q

Suggests the posibility of thyroid lymphoma

A

rapidly enlarging thyroid mass

125
Q

most common type of thyroid lymphoma

A

diffuse large cell lymphoma

126
Q

True or false. Biopsies of thyroid lymphoma is difficult to distinguish from small cell lung cancer or ATC

A

True.

127
Q

True or false. Thyroid lymphoma is sensitive to external beam radiation

A

True.

128
Q

Medullary cancer accounts for how much of thyroid cancer

A

5.00%

129
Q

What are the three familial forms of medullary cancer

A

MEN2A, MEN2B, and familial MTC without other features of MEN

130
Q

Which is more aggressive MEN2A vs MEN2B

A

MEN2B

131
Q

Which is more aggressive, sporadic or familial MTC

A

familial MTC

132
Q

in medullary thyroid cancer, which is a marker of residual or recurrent disease

A

serum calcitonin

133
Q

mutations associated wit meduallary thyroid carcinoma

A

RET mutations

134
Q

Primary management of MTC

A

surgical

135
Q

Differential excluded in workup of RET mutations in MTC

A

pheochromocytoma

136
Q

True or false. MTC tumor cells do no take up radioiodine

A

True.

137
Q

Therapies that provide palliation in MTC patients

A

targeted kinase inhibitors and external radiation

138
Q

What is the prevalence of palpable nodules in adults

A

5.00%

139
Q

True or false. Most patients with thyroid nodules have normal thyroid function tests

A

True.

140
Q

True or false. Lesions with increased uptake are almost never malignant

A

True.

141
Q

Reasons why do a thyroid ultrasound

A
  1. confirm is palpated mass is a nodule. 15% of palpable mass are not confirmed on ultrasound 2. assess additional nodules 3. assess the imaging pattern and size of nodule
142
Q

recommended FNA size cutoff

A

1 cm

143
Q

True or false. The 2015 ATA guidelines does not recommend FNA for any nodules less than 1 cm

A

True.

144
Q

Used widely to provide more uniform terminology for reporting thyroid nodule FNA cytology results

A

Bethseda system

145
Q

Evaluation of thyroid nodules detected by palpation or imaging. Normal or high TSH. What to do next?

A

Diagnostic ultrasound with Lymph node assessment

146
Q

Evaluation of thyroid nodules detected by palpation or imaging.Low TSH. What to do next?

A

Radionuclide scanning

147
Q

Evaluation of thyroid nodules detected by palpation or imaging. Normal or high TSH. Nodule detected on ultrasound. What to do next?

A

FNA based on size and imaging features.

148
Q

Evaluation of thyroid nodules detected by palpation or imaging.Low TSH. Hyperfunctioning nodules. What to do next?

A

Evaluate and treat for hyperthyroidism

149
Q

Evaluation of thyroid nodules detected by palpation or imaging.Low TSH. Nodule not functioning. What to do next?

A

Diagnostic ultrasound with Lymph node assessment

150
Q

Evaluation of thyroid nodules detected by palpation or imaging. Normal or high TSH. Nodule detected on ultrasound. FNA non diagnostic. What to do next?

A

Repeat US guided FNA

151
Q

Evaluation of thyroid nodules detected by palpation or imaging. Normal or high TSH. Nodule detected on ultrasound. FNA showed malignant features

A

Surgery

152
Q

Evaluation of thyroid nodules detected by palpation or imaging. Normal or high TSH. Nodule detected on ultrasound.FNA suspicious for PTC

A

Surgery

153
Q

Evaluation of thyroid nodules detected by palpation or imaging. Normal or high TSH. Nodule detected on ultrasound.FNA suspicious for follicular neoplasm?

A

Consider molecular testing. Surgery if indicated

154
Q

Evaluation of thyroid nodules detected by palpation or imaging. Normal or high TSH. Nodule detected on ultrasound.FNA atypia or follicular lesion of undetermined significance

A

Repeat US guided FNA or molecular testing. Surgery if indicated

155
Q

Evaluation of thyroid nodules detected by palpation or imaging. Normal or high TSH. Nodule detected on ultrasound.FNA showed benign nodule.

A

Follow up.

156
Q

What are the category in the Bethseda Classification for thyroid cytology

A

I nondiagnostic or unsatisfactory II benign III atypia or follicular lesion of unknown significance IV follicular neoplasm V suspicious for malignancy VI malignant

157
Q

Thyroid cancer. Associated with RET mutations, MEN2A and MEN 2B; elevated serum calcitonin

A

Medullary thyroid cancer

158
Q

Thyroid cancer. Well differentiated. Psammoma bodies and orphan Annie nuclei on FNAB. Excelllent prognosis

A

Papillary thyroid cancer

159
Q

Thyroid cancer. Diagnosis is based on capsular invasion. Hematogenous spread

A

Follicular thyroid cancer

160
Q

Thyroid cancer poorly differentiated. Poor prognosis

A

Anaplastic thyroid cancer

161
Q

Thyroid cancer. Usually in the background of Hashimoto’s thyroiditis.

A

Thyroid lymphoma

162
Q

True or false. Staging of PTC and FTC, age less than 45 years old any T any N with metastasis is Stage II

A

True.

163
Q

Thyroid cancer. Age more than 45. stage with metastasis

A

Stage IVC

164
Q

What are the staging in anaplastic thyroid cancer

A

all cases Stage IV