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22 Cards in this Set
- Front
- Back
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What are the indications for thyroid surgery?
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risk/fear of malignancy.
objective compressive findings. ?cosmetic |
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What is the prevalence of thyroid nodules in the population, by palpation, ultrasound or autopsy?
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palpation: 1.5 % men, 6.5 % women. If one is palpated, 50% of the time there are more nodules.
ultrasound: 17-20% men, 20-40% women autopsy: 50% of thyroids by 50 yo, 20% have occult thyroid cancer |
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What size nodule can be palpated by a skilled vs. unskilled observer?
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skilled: 1 cm
unskilled: 1.5-2 cm |
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What's the risk of nodules after head and neck external beam radiation?
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30-40 % have thyroid nodules, 25% of these nodules may be cancerous
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What's the risk of malignancy of a nodule? What increases the risk?
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5-10 %.
Risk increases at <20yo, >60yo, males, head and neck radiation, family history of MEN 2. |
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How is the histology of thyroid nodules distributed?
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70 % colloid
20 % adenomas 10 % carcinomas |
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What are the signs of a malignant nodule?
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hard, fixed, rapid growth, local lymphadenopathy, distant metastases, vocal cord paralysis.
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Why would an ultrasound be used in testing nodules for malignancy?
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can tell solid vs. cystic (slight increase malignancy if solid) and size of the nodule. Not very useful.
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Why would radionuclear scanning be used for testing nodules for malignancy?
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5-10 % of cold nodules are malignant. Almost all hot nodules are not. Not very useful.
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Why would biochemistry be used for testing nodules for malignancy?
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Cancer: TSH is usually normal.
Response to L-thyroxine suppressive therapy decreases risk by 0.7 %. Not very useful. |
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How is fine needle aspiration biopsy used to evaluate nodules for malignancy?
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*gold standard*
simple office procedure, very accurate. On histo: 70% benign (conservative treatment), 5% malignant, 15% suspicious (surgery). sens/spec 98-99% Should be performed on all palpable nodules, initial procedure of choice |
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How should you follow up an incidentaloma?
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<1 cm: low cancer risk --> f/u in 6-12 mo, high cancer risk (microcalcification, growth) --> FNAB
>1 cm: FNAB |
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What types of differentiated follicular epithelium thyroid carcinomas are there?
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papillary (75 %)
follicular (20 %) |
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What is distinctive about papillary thyroid carcinomas?
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well-differentiated follicular epithelium carcinoma.
70-80 % of all thyroid cancers. Women esp ~30yo. mets to regional lympth nodes Excellent prognosis. 20-30% recurrence over several decades |
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What's distinctive about follicular thyroid carcinomas?
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well-differentiated follicular epithelium carcinoma.
20% of thyroid cancers. ~50yo. hematogenous spread to lung and bone. worse prognosis than papillary 20-30% recurrence rate over several decades. |
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What's distinctive about medullary carcinoma?
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well-differentiated interstitium carcinoma.
associated with MEN2 syndrome, 90% sporadic. tumor markers: calcintonin, CEA. Can't be treated with I131. |
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What's distinctive about an anaplastic tumor?
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Rare tumor, 5%, 70 yo.
aggressive and rapidly fatal. |
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What's distinctive about a thyroid lymphoma?
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Rare, 5%
Usually associated with Hashimoto's thyroiditis, large-cell type. |
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How are thyroid carcinomas treated?
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total thyroidectomy followed by radioiodine ablation with I131.
L-thyroxine replacement therapy is initiated and life-long. follow-up: annual I131, serum thyroglobulin test (use rhTSH to keep thyroid levels up during the scan). |
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How much non-toxic goiter is there in the US?
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5% of the population.
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What are some causes for goiters?
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congenital defects in thyroid hormonogenesis, iodine deficiency, goitrogens (lithium, amiodarone).
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What tests should be done on someone with a goiter?
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serum TSH (to determine if eu, hypo, or hyper thyroid), serum antithyroid antibodies.
If euthyroid/hypothyroid, give L-thyroxine to prevent progressive enlargements. |
