Thyroid Nodules & Thyroid Cancer Flashcards
thyroid nodules (adenomas) - overview
*very common, more common with increasing age
*90-95% of thyroid nodules are benign and non-functioning
*some nodules can be toxic and can cause hyperthyroidism; additionally, you can have a toxic multinodular goiter
*the remaining 5-10% are malignant
evaluation of thyroid nodules - 2 questions
- is it a toxic nodule / is it making excess thyroid hormone?
-measure TSH; if low, get radioactive iodine uptake & scan - is it cancer?
-ULTRASOUND, then fine needle biopsy depending on features
what is the best way to evaluate thyroid nodules?
*ULTRASOUND!
*allows us to risk stratify and decide which nodules need to be biopsied
*indications for fine needle aspiration (FNA) biopsy: nodule > 1 cm and has suspicious characteristics
papillary carcinoma of the thyroid - overview
*most common thyroid malignancy; one of the “well-differentiated” thyroid cancers
*cell origin = follicular epithelial cells
*prognosis = good
*tumor marker = thyroglobulin
papillary carcinoma of the thyroid - pathologic features
1. empty-appearing nuclei with central clearing (Orphan Annie eyes)
2. Psammoma bodies: laminated, concentric spherules with dystrophic calcification
*nuclear grooves
*cells form papillae instead of follicles
psammoma bodies - image & associated condition
*laminated, concentric spherules with dystrophic calcification
*associated with papillary carcinoma of the thyroid
orphan annie eyes - image & associated condition
*empty-appearing nuclei with central clearing
*associated with papillary carcinoma of the thyroid
papillary carcinoma of the thyroid - genetic mutation
*BRAF mutation
what is the most well-known risk factor for development of well-differentiated (papillary or follicular carcinoma) thyroid cancer?
*history of RADIATION to the neck
papillary carcinoma of the thyroid - treatment
*SURGERY +/- radioactive iodine +/- TSH suppression (via extra levothyroxine)
*sometimes, we just watch the cancers and wait
complications associated with thyroidectomy
*transient or permanent hypoparathyroidism (parathyroid glands can be either “stunned” or removed/permanently damaged)
*damage to recurrent laryngeal nerve: results in hoarse voice, trouble swallowing
*damage to external branch of superior laryngeal nerve: primarily affects singing voice
follicular carcinoma of the thyroid - overview
*well-differentiated thyroid cancer; good prognosis
*invades tumor capsule and vasculature, uniform follicles
*pathologic feature = microfollicles
*associated gene mutations: RAS, PAX8-PPAR gamma
*tumor marker = thyroglobulin
thyroglobulin as a tumor marker
*we measure thyroglobulin to check for recurrence in well-differentiated (papillary, follicular) thyroid cancer
*thyroglobulin: a precursor for thyroid hormone, and used to store thyroid hormone in the follicles once made; only comes from thyroid tissue
*if a person has a total thyroidectomy, the thyroglobulin should be undetectable; if it is increasing, this suggests thyroid cancer recurrence
medullary thyroid cancer - overview
*cell origin = C-cell (parafollicular cells)
*characterized by amyloid deposition (stains with Congo red) on pathology
*tumor marker = calcitonin
medullary thyroid cancer - associated gene mutation
*RET mutation:
- about 25% associated with MEN2A or MEN2B syndrome
