Thyroid Disease III (thyroid nodules)

describe typical presentation of thyroid nodules:

• single or multiple nodules are common

• most are less than or equal to > 1cm

• most are asymptomatic

if a thyroid nodule is detected, what is the next step?

• must determine clinical relevance

• rule out malignancy

• evaluate thyroid function testing and malignancy

how common are thyroid nodules?

4-7% of adults

what are risk factors of thyroid nodules?

• females

• older age

• smokers

• iodine deficiency

what is pertinent PMH for an increased risk of malignancy?

• head-neck radiation

• total body radiation

• exposure to fall-out as a child

• other malignancy

what are concerning clinical presentations associated with increased risk of malignancy?

• hoarseness

• vocal cord

• paralysis

• adherence to trachea or strap muscles

• cervical lymphadenopathy

• nodule that is solitary and/or greater than 4.5 cm

how can nodules be detected?

by having the patient swallow during inspection and palpation

what may be some symptoms of a nodules if the growth is large enough?

• discomfort

• hoarseness

• dysphagia

what can large substernal nodules cause?

superior vena cava syndrome

what can nodules be associated with?

• hypothyroidism

  • Hashimoto, iodine deficiency

• hyperthyroidism

  • Graves, subacute thyroiditis, thyroid cancer with mets

• neither

what the differential diagnoses of thyroid nodules?

• iodine deficiency

• Graves/Hashimoto

• acute/subacute thyroiditis

• medication

• malignancy/sarcoidosis

• lymphadenopathy, lymphoma, cyst

what are the initial labs that should be ordered for assessing thyroid nodules?

TSH and free T4

what should be done next if the TSH was low?

radioiodine scan

what is the difference between a hot nodule and a cold nodule?

• hot: not malignant

• cold: malignant

what are some additional labs you can order?

• thyroid autoantibodies (Hashimoto thyroiditis)

• serum calcitonin (thyroid carcinoma)

what is the preferred imaging study for thyroid nodules?

neck ultrasound

what features found on ultrasound indicate very low risk of malignancy?

spongiform or simply cysts

what features found on ultrasound indicate low risk of malignancy?

partially cystic with eccentric solid areas

what features found on ultrasound indicate intermediate risk of malignancy?

hypoechoic or solid

what features found on ultrasound indicate high risk of malignancy?

microcalcifications, irregular margins, extrathyroidal extension, taller than wide, asymmetrical

what are indications for a CT scan?

• problems breathing swallowing, etc

  • determine degree of tracheal compression and extension to mediastinum

• increased risk of malignancy based on ultrasound

what are high risk of malignancy findings based on ultrasound?

heterogenous hypoechoic, > 2mm growth per year

what are indications for an ultrasound guided fine needle aspiration and biopsy?

• > 1cm with normal or increased TSH

• > 1cm with decreased TSH and cold nodules

• high risk finding on ultrasound

what is treatment for nodules greater than 2cm and/or an increased or normal TSH?

suppression therapy with levothyroxine

what are indications for surgical resection?

• solitary nodule in patient with history of head-neck radiation

• toxic adenoma to cure hyperthyroidism

• compressive symptoms

• malignancy found of FNA biopsy

what are types of ablation therapy?

• US guided radiofrequency

• US guided alcohol ablation

• radioactive iodine

when should US guided radiofrequency ablation be used?

benign nodules > 3cm and predominately solid

when should US guided alcohol ablation be used?

cystic nodules not associated with Graves

when should radioactive iodine ablation be used?

hyperthyroid patients with toxic adenomas, multinodular goiter, Graves

what are the 4 types of thyroid cancer?

• papillary

• follicular

• medullary

• anaplastic

describe papillary and follicular thyroid cancer:

common with a good prognosis

describe medullary thyroid cancer:

Rare, good prognosis if the cancer is restricted to the thyroid gland. Bad prognosis if there are mets present

describe anaplastic thyroid cancer:

rare, rapid growing and poor prognosis

what is the epidemiology of thyroid cancer?

• 540,000 adult cases per year

• 5th most common cancer in women

• found in 10% of first degree relatives with papillary thyroid cancer

describe the epidemiology of thyroid cancer pertaining women:

• women are 3x more likely than men

• most common cancer in women 20-34 years of age

what is the only modifiable risk factor of thyroid cancer?

thyroid irradiation

what are alarming findings of thyroid cancer?

• rapid growth over weeks to months

• tracheal compression/invasion

  • dyspnea, cough, hemoptysis

• posterior invasion

  • recurrent laryngeal nerve palsy, vocal cord dysfunction, hoarseness

what are signs and symptoms of thyroid cancer?

• most are asymptomatic and diagnosed on routine exam/ incidental finding

• possible symptoms include neck mass, hoarseness, lymphadenopathy, dysphagia, dyspnea, cough

what findings of PE can indicate thyroid cancer?

• greater than 1cm nodule require evaluation (swallow test)

• ipsilateral lymphadenopathy

• superior vena cava syndrome

what are initial diagnostic studies done when dealing with thyroid cancer?

TSH and free T4

what diagnostic study should be done next if TSH is increased or normal?

fine needle aspiration and biopsy

what diagnostic study should be done next if TSH decreased?

radioiodine scan

If a hot nodule is found on radioiodine scan what is next?

evaluate for hyperthyroidism

if a cold nodule is found on radioiodine scan what is next?

FNA and biopsy

what are US findings that indicate the need for FNA and biopsy?

• hypoechoic

• calcifications

• infiltrative margins

• increased central vascularity

• unilateral adenopathy

what is treatment for thyroid cancer?

• near total or total thyroidectomy

• radioiodine ablation

• external beam radiation

what treatment is recommended for patients with differentiated thyroid cancer?

near-total or total thyroidectomy

what are indications for a total thyroidectomy?

• tumor greater than 1 cm

• US: additional nodules on contralateral lobe

• FHx of thyroid cancer

• PMHx head neck radiation

what are indications for radioiodine ablation?

• distant mets

• extrathyroidal extension of tumors

• tumor > 4cm

what are indications for external beam radiation?

palliative treatment if the cancer is locally advanced or unresectable in patients older than 45

what does cancer treatment cause? what needs to be done?

• hypothyroidism

• levothyroxine therapy

what should be monitored after thyroid cancer treatment?

TSH and free T4, periodic US exams