Thyroid Noudle

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Prevalence and incidence Palpable nodules: 4-7% of the population Incidentally on US: almost 50 %,

75 % multi nodular, 25 % solitary Thyroid cancer: 5-10 % of palpable nodules The main objective of evaluating thyroid nodules is to

exclude malignancy

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Type of thyroid nodules

Cyst: simple cyst, mixed cystic-solid Colloid nudule: dominant nodule in MNGAdenoma: Follicular, Hurthle cell, Atypical Thyroiditis: Hashimoto’s, subacute Infection: Granulomatous disease, Abscess Developmental anomalies: unilateral lobe agenesis,

cystic hygroma, Dermoid, TeratomaCarcinoma: papillary (75%), follicular ( 5-10%),

medullary (5-10%), anaplastic (5%),lymphoma (5%), metastatic

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Factors associated with increase risk for malignant thyroid nodule History (moderate increase risk)

Age < 20 or > 60 years Male sex Exposure of RT (especially in childhood) F.Hx of thyroid cancer or polyposis

Physical finding (highly increase risk) larger than 3 cm Rapid tumor growth Very firm nodule, irregular surface Fixation to adjacent structure Symptom of local invasion: dysphagia, hoarseness Cervical lymphadenopathy Cold nodule on thyroid scan Solid or complex cyst on US

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Factors suggesting benign thyroid nodule

F.Hx of autoimmune disease (Hashimoto’s thyroiditis) F.Hx of benign thyroid nodule or goiter Presense of thyroid hormone dysfunction,

hypothyroid or hyperthyroid Pain or tenderness associated with nodule Soft, smooth, mobile MNG without a predominant nodule Warm nodule on thyroid scan Simple cyst on US

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Investigation1. Laboratory evaluation

TSH: screening for hyper or hypothyroidT3, T4 : when TSH are low normal or high normalSerum antithyroid peroxidase (anti-TPO),

antithyroglobulin (anti-Tg) if suspected thyroiditis 2. Imaging study

CT, MRI, PET: not cost-effective in initial evaluation of thyroid nodule

Ultrasound: characters that increase risk for malignant; ill defined margin, irregular shape, solid echo, hypoechoic,calcification (fine): sensitivity 75 %, specificity 61 %

Thyroid isotope scanning: 131 I, 123I, 99TC

cold nodule (84%): cancer risk 15%warm nodule (10.5%): cancer risk 9%hot nodule (5.5%): cancer risk 1%

Thyroxine suppression therapy with US follow up

sensitivity 83%, specificity 33%

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US:US: A solitary hypoechoic nodule at A solitary hypoechoic nodule atRt. Lobe thyroidRt. Lobe thyroid

Slide 12Slide 12

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Isotope scanIsotope scan: Left: Normal thyroid: Left: Normal thyroid

Right: A cold nodule Right: A cold nodule Lt.lobe thyroidLt.lobe thyroid

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Diagnostic procedure:

Fine needle aspiration cytology (FNA)

Sensitivity: 70-90%, specificity 70-90% False negative result: 3-8 % Reliability depend on:

Operator Cytopathologist Type of tumor: follicular neoplasm has

20-30% false negative rate

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Thyroid Nodule

TSH test

Euthyroid Thyrotoxic

Thyroid scan

FNA Cold nodule Hot nodule

131 I or surgeryBenign Suspicious Malignant Inadequate

Observe or T4-Px Surgery Repeat FNAFU 6-12 M

Suggested strategy for the management of thyroid nodules

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Thyroid incedentalomas

Incidence: 30-60% (Autopsy), 13-50% (Ultrasound) Size: usually < 1.5 cm Incidence of cancer: < 5 %, mostly papillary CA

Thyroid incedentaloma

Hx. H+N RT, F.Hx. CA thyroid

Positive Negative

US guide FNA US finding

CytologySuspected Benign appearance

Malignant or (< 1.5 cm)(> 1.5 cm)

Observe

Malignant Benign

Surgery Observe

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Frequency Malignant histologyBenign 60-65% 3-8 %

Colloid or nodule goiter Thyroiditis

Suspicious 10-15% 20-30% Follicular neoplasm Hurthle cell lesion Cellular smear Lymphoma

Malignant 3-5% 95% Papillary Medullary Anaplastic

Inadequate 15% 5% Techincal problem Degernerative nodule Hemorrhagic cyst

Result of thyroid FNA interpretation

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Colloid nodule:

A: FNA B: Histopathology

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Hoshimoto’s thyroiditis

A: FNA B: Histopathology

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Papillary carcinoma:

A: FNA B: Histopathology

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A: FNA B: Follicular adenoma

C: Follicular carcinoma