thyroid nodules and cancer

discreet lesions within the thyroid gland that are radiologically distinct from the surrounding tissue

thyroid nodules

what population tends to have more thyroid nodules

more common in women and older adults, inc prevalence w age

types of thyroid nodules

adenoma, colloid nodule, cyst

are most thyroid nodules benign or malignant

90% of palpable nodules are benign

a fluid filled benign thyroid nodule

thyroid cyst

a benign thyroid nodule full of excess colloid

colloid nodule

a benign encapsulated thyroid nodule

adenoma

the most common type of thyroid nodule, solid and well defined and usually nonfunctional (which makes it easier to take out)

colloid nodule

nodules may be solid or cystic, and are occasionally hyperfunctional (hyperthyroidism sx and tx), lumpy looking

multinodular goiter

autoimmune cause, nodules caused by diffuse changes in the thyroid due to inflammation and fibrosis

hashimotos thyroiditis

fluid filled, can either be simple (fluid only) or complex (some solid components) and may have some blood or may not

cysts

typically encapsulated, solid, round, well-circumscribed solid borders

follicular adenomas

the most common type of thyroid cancer (80%)

papillary carcinoma

10-15% of thyroid cancers are this kind, good prognosis but higher chance of spreading

follicular carcinoma

only 4% of thyroid cancers, these arise from c cells (parafollicular cells) which can inc calcitonin (also dont give these pts GLP-1 agnoists)

medullary carcinoma

a rare (2%) and aggressive type of thyroid cancer

anaplastic carcinoma

a rare thyroid cancer associated w hashimotos

primary thyroid lymphoma

secondary lesions that metastisized to thy thyroid from other parts of the body (lungs, breast, kidneys, melanoma)

metastatic disease

if your pt is an older woman and has a thyroid nodule thats soft/multinodular/can be moved around, looks cystic on ultrasound, has a hot nodule on radioactive iodine test, and the pt has high antibody titers and a family hx of goiter should we be freaking out or chillin

chillin, these are low index of suspicion

what thyroid problems have a high Radioactive iodine Uptake (looks dark)

graves, toxic multinodular goiter, toxic adenoma

what thyroid problems have a low Radioactive iodine Uptake (looks light)

thyroiditis, iodine overload, exogenous thyroid hormone use

what does a high RAIU indicate

lots of iodine is being pulled in and used by the thyroid actively

thyroid nodules that are “hot” (aka functional aka high RAIU) indicate what

usually benign nodules

thyroid nodules that are “cold” (aka non-functional aka low RAIU) indicate what

need further eval bc higher cancer risk

why is using radioactive iodine uptake a good tool for staging and treating thyroid cancer

helps identify residual thyroid tissue or metastatic disease after a thyriodectomy (will be “hot” when it shouldnt be)

if your thyroid nodule pt is a young adult w a family hx of cancer and previous hx of radiation exposure and they come in with elevated calcitonin, a solid nodule on ultrasound, a cold nodule on RAIU test, and the nodule is taller than it is wide with microcalcifications, irregular margins, and hypoechoic texture (darker than surrounding tissue) and extrathyroidal extensions should we be freakin out or chillin

freaking out thats cancer dude (high index of suspicion)

what may you see on physical examination for a pt w a thyroid nodule

nail clubbing, hair changes, shaking hands, sweaty, brady/tachycardia, palpable thyroid gland, bulging eyes

what labs and tests can we do when evaluating thyroid nodules

TSH, free T3 and T4, thyroid antibodies (hashimotos), ultrasound to assess sonographic features, additional nodules and lymphadenopathy

how are most thyroid nodules found

incidentally (asymptomatic)

symptoms of thyroid nodules

pain, pressure, hard to swallow or breathe (rare)

sx of thyroid nodules that suggest malignancy

hard fixed nodules, rapid growth, vocal cord paralysis (hoarse throat),irregular boarders, over 2cm, taller than wide shape

what kind of biopsy do we do on thyroid nodules

fine needle aspiration (FNA)

when are fine needle aspirations indicated

for thyroid nodules w suspicious features on ultrasound or if the nodule is over 1cm

what is the bethesda scale

1-6 scale of categories to assess if a thyroid nodule is benign or malignant (1 is benign, 6 is malignant)

what is definitive for thyroid cancer dx

only definitive is when you get in there to take the whole thyroid out to study it (FNA is NOT definitive)

features of papillary thyroid carcinoma

most common, least aggressive thyroid cancer

often presents as a single nodule and can metastasize via lymphatics

prognosis is great even when it spreads

Tx w total thyroidectomy if tumor is over 1cm, do central neck dissection if lymphadenopathy present

features of papillary thyroid carcinoma

more aggressive than papillary carcinoma

absorbs a ton of radioactive iodine (high RAIU)

metastasizes to bone and lungs

tx w total thyroidectomy and Radioactive iodine therapy for metastatic disease

features of medullary thyroid carcinoma

associated w MEN 2 syndromes

requires genetic testing for RET mutations

poor iodine uptake

metastasizes early

features of anaplastic thyroid carcinoma

most aggressive, bad prognosis

presents w rapidly enlarging mass and compressive sx

how do we treat thyroid cancer

lobectomy if its small and well defined, total thyroidectomy if over 1cm tumor or aggressive caner

radioactive iodine therapy if high risk or some tissue remains post-thyroidectomy

lifelong thyroid hormone replacement therapy