378 Thyroid Nodules Flashcards
1
Q
Weight of thyroid gland
A
12-20 grams
2
Q
Drugs that prevent the peripheral conversion of thyroid hormones
A
PTU
Propranolol
Glucocorticoids
Amiodarone
3
Q
Half life of T3
A
2 days
4
Q
True or false. Right lobe of thyroid is larger than the left
A
True
5
Q
Percentage of T4 coming from the thyroid
A
100%
6
Q
Percentage of T3 coming from thyroid
A
20%
7
Q
RAI contraindication
A
Pregnancy
Breastfeeding
8
Q
When does thyroid synthesis begin
A
11 weeks gestation
9
Q
Where does the thyroid gland develop
A
Floor of the primitive pharynx during 3rd week of gestation
10
Q
Failure of the thyroid gland to migrate in the neck and is found at the base of the tongue
A
Lingual thyroid
11
Q
Gives rise to calcitonin
A
Thyroid medullary C cells
12
Q
Where are the C cells located
A
Upper 1/3
Lower 2/3
Of thyroid gland
13
Q
Orchestrate thyroid gland development
A
Homeobox-8 (PAX 8)
14
Q
Where are the follicular cells of the thyroid located
A
Basolateral surface
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
16
Q
What hormones are similar to the TSH alpha unit
A
LH
FSH
hCG
17
Q
Suppresses TSH
A
Dopamine
Glucocorticoids
Somastostatin
18
Q
Major positive regulator of TSH
A
TRH
19
Q
Critical first step in thyroid hormone synthesis
A
Iodine uptake
20
Q
Mediated iodide uptake, expressed in the basolateral membrane of the follicular cells
A
NIS (Sodium iodide symporter)
21
Q
Low levels of NIS is expressed in which organs
A
Salivary glands
Lactating breast
Placenta
22
Q
Iodine transporter in the basolateral surface? On the apical surface?
A
Basolateral: NIS
Apical: pendrin
23
Q
Disorder characterized by defective organification of iodine, Goiter had sensorinueral deafness
A
Pendred syndrome
24
Q
Characterized by mental and growth retardation in iodine deficient regions
A
Cretinism
25
Concomitant deficiency in cretinism that contribute to neurologic manifestation
Selenium deficiency
26
Recommended average daily intake of iodine
150-250 ug/day
27
Disorders of thyroid hormone synthesis is due to what mutations
Recessive mutations of TPO or Tg
28
Excess iodide transiently inhibits thyroid iodide organification
Wolf chaikoff phenomenon
29
Types of deiodinases. Where are they found
Type I: low affinity, thyroid, liver and kidneys
Type II: strong affinity, pituitary, brain, brown fat, thyroid
Type III: most import source of rT3
30
Caused by self administration of thyroid hormone
Thyrotoxicosis factitia
31
Increased in all type of Thyrotoxicosis except Thyrotoxicosis factitia
Serum Tg
32
Main role of Tg measurement
Follow up thyroid cancer
33
Hot vs cold nodule on thyroid scintigraphy
Hot: never malignant
Cold: likely malignant
34
Most common type of thyroid cancer
Papillary thyroid cancer
35
Characteristic cytologic features of PTC
psammoma bodes, cleaved nuclei with orphan annie appearance
36
Where does follicular thyroid cancer spread?
hematogenously to bone, lung, and CNS
37
Main stay of thyroid cancer treatment as most tumors are TSH responsive
levothyroxine suppression
38
Aggressive thyroid cancer and patient often die 6 months of diagnosis
anaplastic thyrpid cancer
39
True or false. lymphoma in the thyroid gland often arises in the background of Hashimotos thyroiditis
True
40
Most common type of thyroid lymphoma
Diffuse large cell lymphoma
41
refers to an enlarged thyroid gland
goiter
42
True or false. Graves' disease and Hashimoto's thyroidism are also associated with goiter
True.
43
pathogenesis of goiter in Grave's disease
TRH mediated effects of thryoid stimulating immunoglobulin
44
pathogenesis of goiter in Hashimoto's thyroidism
goitrous form pccurs because of acquired defects in hormone synthesis, leading to elevated levels of TSH and its consequent growth effects
45
Diffuse enlargement of the thyroid in the absence of nodules and hyperthyroidism
diffuse nontoxic goiter
46
other name of diffuse nontoxic goiter
simple goiter, colloid goiter
47
most common cause of diffuse goiter worldwide
iodine deficiency
48
thyroid enlargement in teenagers
juvenile goiter
49
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
True.
50
what is the action of iodine to thyroid growth
direct actions on thyroid vasculature and indirectly affect growth through vasoactive substances such as endothelin and nitric oxide
51
abnormal thyroid volume on ultrasound
more than 30 ml
52
refers to the facial and neck congestion due to jugular venous obstruction when the arms are raised above the head
Compression exceed 70% of the tracheal diameter
53
manuever that draw the thyroid to the thoracic inlet
Pembertons sign
54
associated with Pemberton signs
substernal goiter
55
laboratory findings that support iodine deficiency
low urinary iodine levels less than 50 ug/L
56
True or false. Iodine replacement induces variable regression of goiter in iodine deficiency depending on the duration and degree of hyperplasia
True.
57
conditions where surgery is indicated in diffuse goiter
tracheal compression or obstruction of the thoracic inlet
58
True or false. Surgery is rarely indicated for diffuse goiter
True.
59
True or false. TSH is play an permissive or contributory role in nontoxic multinodular goiter
True.
60
True or false. Most patients with nontonic multinodular goiter are asymptomatic and euthyroid
True.
61
What leads to hoarseness of voice in patient with goiter
laryngeal nerve involvement
62
True or false. Pain and hoarseness of voice in goiter suggests malignancy
True.
63
At what level can tracheal compression lead to significant airway compromise
Compression exceed 70% of the tracheal diameter
64
sonographic features assocaited with thyroid cancer
hypoechoic compared with surrounding thyroid, marked hypoechogenicity, microcalcifications, irregular microlobulated margins, solid consistency, taller than wide shape on transverse view
65
characterized by enhanced thyroid production by autonomous nodules
Jod Baselow effect
66
can be used when surgery is contraindicated in areas where large nodular goiter are more prevalent
radioiodine
67
action of radioiodine in toxic nultinodular goiter
decrease MNG volume and may selectively ablate regions of autonomy
68
usual dosage of 131I
3.7 Mbq (0.1 mCi) per gram of tissue, corrected for uptake 370- 1070 Mbq (10-29 mCi)
69
administered concomitantly with 131I to increase effectiveness
TSH 0.1 mg IM
70
True or false. Spontaneous remission on toxic multinodular goiter does not occurs as compared to Graves disease so treatment is lifelong
True.
71
treatment of choice for toxic multinodular goiter
radioiodine
72
solitary autonomously functioning thyroid nodule
toxic adenoma
73
pathogenesis of toxic adenoma
mutations in the TSH-R
74
less common mutations seen in toxic adenoma
Gsa mutations
75
activating mutations identified in more than 90% of patients with toxic adenoma
active mutations in the TSH-R or Gsa
76
in hyperfunctioning solitary nodule, when is thyrotoxicosis generally detected
when nodule is more than 3 cm
77
provides definitive diagnostic test for hyperfunctioning solitary nodule
thyroid scan
78
treatment of choice for hyperfunctioning solitary nodule
radioiodine ablation
79
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
True.
80
adenoma composed of oncocytic follicular cells arranaged in follicular pattern
Hurthle cell adenoma
81
can follicular carcinoma be diagosed by FNA
microcystic areas comprise more than 50% of the nodule volume
82
diagnostic procedure of choice to evaluate thyroid nodules
FNA with ultrasound guidance
83
when should levothyroxine therapy be discontinue in thyroid nodule
no decrease in size after 6-12 months of therapy
84
what is the target TSH when giving levothyroxine in patients with thyroid nodule
TSH should be maintaiend just the lower limit of normal
85
most common malignancy of endocrine system
thyroid cancer
86
thyroid cancer with good prognosis
papillary thyroid cancer and follicular thyroid cancer
87
thyroid cancer associated with a bleak progosis
anaplastic thyroid cancer
88
True or false. Thyroid cancer is twice as common in women as men but male gender is associated with worse prognosis
True.
89
risk factors for thyroid carcinoma in patients with thyroid nodule
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
True or false. Anaplastic thyroid cancer has only one stage, Stage IV
True.
91
True.
more than 4 cm or with tumor extention
92
more than 4 cm or with tumor extention
T1a less than 1 cm, T1b more than 1 cm but less than 2 cm
93
T2 in thyroid cancer
More than 2 cm but not more 4 cm
94
True or false. Higher TSH levels are associated with increased thyroid cancer risk
True.
95
mutations relatively specific for thyroid neoplasm
RET/PTC, PAX8-PPAR gamma 1
96
mutations associated with loss of iodine uptake by tumor celle
BRAF V600E
97
Most common type of thyroid cancer
papillary thyroid carcinoma
98
associated with large clear nuclei with powdery chromatin with nuclear grooves and prominent nucleoli
orphan Annie eyes in PTC
99
thyroid cancer more common in iodine deficient regions
follicular thyroid cancer
100
Can follicular carcinoma be diagosed by FNA
No
101
Why cant FTC be diagnosed on FNA
distinction between benign and malignant follicular cells require histology as nuclear features of follicular adenoma and carcinomas do not differ
102
differentiate follicular carcinoma from adenoma
in carcinoma, there is presence of capsular or vascular invasion
103
Spread of PTC
lymphatics but also hematogenously
104
Spread of FTC
hematogenous
105
initial surgical procedure for thyroid cancer more than 1 cm but less than 4 cm
unilateral (lobectomy) or bilateral (near total thyroidectomy)
106
unilateral (lobectomy) or bilateral (near total thyroidectomy)
bilateral surgery and radioiodine for remnant ablation
107
True or false. Most thyroid tumor are TSH responsive
True.
108
Mainstay of thyroid cancer treatment
levothryoxine suppresion of TSH
109
TSH level for those with known metastatic disease
TSH less than 0.1 mIU/L
110
TSH level for low risk of recurrence
lower normal limit 0.5-2.0 mIU/L
111
TSH level for intermediate risk for recurrence
0.1-0.5 mIU/L
112
TSH level for high risk for recurrence
less than 0.1 mIU/L
113
what is the TSH level at the time of 131I therapy
more than 25 mIU
114
Strategy of remnant ablation
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
sensitive marker of residual/ recurrent thyroid cancer after ablation of the residual postsurgical thryoid tissue
serum thyroglobulin
116
Where is the common recurrence of PTC
cervical lymph nodes
117
what should be performed post ablation in PTC
neck ultrasound 6 months after thyroid ablation
118
True or false. ATC has poor prognosis and most patients die within 6 months of diagnosis
True.
119
True or false. Neck ultrasound is more sensitive than whole body scan in detecting recurrences of PTC in cervical lymph nodes
True.
120
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
less than 3% at 5 years
121
what is the Tg level to get 3% recurrence at 5 years
Tg less than 0.2 mg/ml
122
True or false. In ATC due to undifferentiated state of these tumors, the uptake of radioiodine is usually negligible
True.
123
Lymphoma in the thryoid gland often arise in the background of what thyroiditis
Hashimoto's thyroiditis
124
Suggests the posibility of thyroid lymphoma
rapidly enlarging thyroid mass
125
most common type of thyroid lymphoma
diffuse large cell lymphoma
126
True or false. Biopsies of thyroid lymphoma is difficult to distinguish from small cell lung cancer or ATC
True.
127
True or false. Thyroid lymphoma is sensitive to external beam radiation
True.
128
Medullary cancer accounts for how much of thyroid cancer
5.00%
129
What are the three familial forms of medullary cancer
MEN2A, MEN2B, and familial MTC without other features of MEN
130
Which is more aggressive MEN2A vs MEN2B
MEN2B
131
Which is more aggressive, sporadic or familial MTC
familial MTC
132
in medullary thyroid cancer, which is a marker of residual or recurrent disease
serum calcitonin
133
mutations associated wit meduallary thyroid carcinoma
RET mutations
134
Primary management of MTC
surgical
135
Differential excluded in workup of RET mutations in MTC
pheochromocytoma
136
True or false. MTC tumor cells do no take up radioiodine
True.
137
Therapies that provide palliation in MTC patients
targeted kinase inhibitors and external radiation
138
What is the prevalence of palpable nodules in adults
5.00%
139
True or false. Most patients with thyroid nodules have normal thyroid function tests
True.
140
True or false. Lesions with increased uptake are almost never malignant
True.
141
Reasons why do a thyroid ultrasound
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
recommended FNA size cutoff
1 cm
143
True or false. The 2015 ATA guidelines does not recommend FNA for any nodules less than 1 cm
True.
144
Used widely to provide more uniform terminology for reporting thyroid nodule FNA cytology results
Bethseda system
145
Evaluation of thyroid nodules detected by palpation or imaging. Normal or high TSH. What to do next?
Diagnostic ultrasound with Lymph node assessment
146
Evaluation of thyroid nodules detected by palpation or imaging.Low TSH. What to do next?
Radionuclide scanning
147
Evaluation of thyroid nodules detected by palpation or imaging. Normal or high TSH. Nodule detected on ultrasound. What to do next?
FNA based on size and imaging features.
148
Evaluation of thyroid nodules detected by palpation or imaging.Low TSH. Hyperfunctioning nodules. What to do next?
Evaluate and treat for hyperthyroidism
149
Evaluation of thyroid nodules detected by palpation or imaging.Low TSH. Nodule not functioning. What to do next?
Diagnostic ultrasound with Lymph node assessment
150
Evaluation of thyroid nodules detected by palpation or imaging. Normal or high TSH. Nodule detected on ultrasound. FNA non diagnostic. What to do next?
Repeat US guided FNA
151
Evaluation of thyroid nodules detected by palpation or imaging. Normal or high TSH. Nodule detected on ultrasound. FNA showed malignant features
Surgery
152
Evaluation of thyroid nodules detected by palpation or imaging. Normal or high TSH. Nodule detected on ultrasound.FNA suspicious for PTC
Surgery
153
Evaluation of thyroid nodules detected by palpation or imaging. Normal or high TSH. Nodule detected on ultrasound.FNA suspicious for follicular neoplasm?
Consider molecular testing. Surgery if indicated
154
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
Repeat US guided FNA or molecular testing. Surgery if indicated
155
Evaluation of thyroid nodules detected by palpation or imaging. Normal or high TSH. Nodule detected on ultrasound.FNA showed benign nodule.
Follow up.
156
What are the category in the Bethseda Classification for thyroid cytology
I nondiagnostic or unsatisfactory II benign III atypia or follicular lesion of unknown significance IV follicular neoplasm V suspicious for malignancy VI malignant
157
Thyroid cancer. Associated with RET mutations, MEN2A and MEN 2B; elevated serum calcitonin
Medullary thyroid cancer
158
Thyroid cancer. Well differentiated. Psammoma bodies and orphan Annie nuclei on FNAB. Excelllent prognosis
Papillary thyroid cancer
159
Thyroid cancer. Diagnosis is based on capsular invasion. Hematogenous spread
Follicular thyroid cancer
160
Thyroid cancer poorly differentiated. Poor prognosis
Anaplastic thyroid cancer
161
Thyroid cancer. Usually in the background of Hashimoto's thyroiditis.
Thyroid lymphoma
162
True or false. Staging of PTC and FTC, age less than 45 years old any T any N with metastasis is Stage II
True.
163
Thyroid cancer. Age more than 45. stage with metastasis
Stage IVC
164
What are the staging in anaplastic thyroid cancer
all cases Stage IV
