Most likely diagnosis? a)Graves disease b)Hashimotos disease
c)Multifocal papillary cancer d)Anaplastic thyroid cancer
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Most likely diagnosis? [ 4 mos. s/p thyroidectomy for CA]
a)Residual thyroid tissue b) Gelfoam in surgical bed c)Recurrent
cancer d)Lymphadenopathy
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Anatomy
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Normal Thyroid Gland: Transverse
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Trachea Strap Muscles Rt IJV Rt CCA Sternomastoid
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Normal Thyroid Gland: Sagittal CranialCaudal
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Volume Thyroid Gland LengthWidthThickness Volume ellipsoid = L
x W x T / 0.5 Normal Adult Range (Rt + Lt lobes) = 8 15 ml
Correlation with height, surface area
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Indications for Thyroid U/S Evaluation /detection of nodules
YES Guidance for FNA YES Thyroid dysfunction LIMITED Weight loss,
dysphagia, fatigue, neck pain WEAK AACE, ATA, ACP
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I. DIAGNOSIS
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Thyroid Nodules Palpation 4-8 % adult population U/S 50-65% CT
scan, PET-CT, or .. metastasis
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Incidence of malignancy in a nodule 5-15% Whether palpable or
not Whether single or multiple
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Thyroid Cancer Papillary 80% Follicular 15% (Hurthle cell)
Medullary : 3% familial, MEN Anaplastic: 2% highly aggressive
Differentiated cancer
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Large reservoir of clinically occult thyroid cancer in general
population 1947 NEJM : VanderLaan - occult PCT common autopsy
finding in persons with no history of thyroid disease 1985 Cancer
1985: HR Harach et al (Finland)- thyroid cut in 1 mm. blocks,
occult cancer in 35%. If cut thinly enough, would find PTC in
almost every Finish thyroid gland
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A Dilemma (National Cancer Institute data) 240% increase Stable
Increased incidence mainly due to 1-2 cm papillary cancers
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Method of Detection Palpation (4%) Ultrasound (50-67%)
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Conclusion increasing incidence reflects increased detection of
subclinical disease, not an increase in the true occurrence of
thyroid cancer Davies L, Welch HG. JAMA 2006; 295:2164-2167.
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Real Increase in Incidence? the incidence rate of
differentiated thyroid cancers of all sizes increased across all
tumour sizes between 1998 and 2005 in both men and women this
suggest that increased diagnostic scrutiny is not the sole
explanation Chen AY. Cancer 2009; 115: 3801-3807.
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Basis for management of thyroid nodules Ultrasonography (US),
Thyrotropin (TSH) assay, Fine-needle aspiration (FNA) biopsy
Thyroid scintigraphy is not necessary for diagnosis in most cases
AACE Guidelines
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When to Perform Thyroid Scintigraphy Thyroid nodule (or MNG) if
the TSH level is supressed Hot nodule: benign ; no need for FNA
AACE Guidelines
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FNA
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Pattern Recognition
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FNA recommendations AACE 2010ATA 2009SRU 2005 High Riskall5
mmn/a Abnormal nodesall Microcalcification< 10 mm10 mm Solid
hypoechoic10 mm10 -15 mm15 mm Mixed cystic/solid10 mm15 -20 mm20 mm
Spongiformn/a20 mmn/a Purely cysticno Risk Malignancy
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Biopsy / Mortality per 100,000 Hammond I, Schweitzer ME. A
Resource Allocation Metric for Thyroid Biopsies. J Am Coll Radiol
2011;8:49-52
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5 Benign leave-alone patterns Colloid cyst Spongiform nodule
Cyst with colloid clot Giraffe pattern White knight Bonavita et al.
AJR 2009; 193: 207213
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(1)Colloid Cyst: Comet Tail
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(2,3) Benign Colloid Nodule Spongiform Cyst with Colloid Clot *
* can mimic cystic changes in cancer
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(4,5)Hashimotos disease Giraffe Pattern White Knight
General principles of treatment: Remove 1 tumor disease
extended beyond the thyroid capsule involved cervical lymph nodes
Radioactive Iodine AbIation, where appropriate.
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III. Surveillance
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Surveillance Neck U/S Serum thyroglobulin (Tg) Whole body
iodine scan (WBS) PET / CT Low Risk
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Serum Thyroglobulin (Tg) Prohormone of T4 and T3 After total
thyroidectomy and radioiodine ablation Tg should be undetectable in
case of complete remission
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Cervical Nodes III: middle jugular IV: low jugular VI : thyroid
bed VII: paratracheal
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Recurrence thyroid bed: thyroidectomy 8 yrs ago rising Tg CCA
Tr
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Pitfall gelfoam in surgical bed Tublin ME et al. J Ultrasound
Med 2010; 29: 117-120.
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Gelfoam: Thyroidectomy May 2009 July 2009 Dec 2009
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Lymph Node recurrence: thyroidectomy with RAI - rising Tg
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Teaching Points 1 Papillary cancer = most common Nodule w/u:
TSH, U/S If TSH suppressed -> nuclear scan Pattern Recognition:
colloid cyst, spongiform nodule giraffe pattern (white knight) =
BENIGN Cyst with colloid clot can mimic cystic cancer 85% nodules
non-specific morphology