Thyroid Nodules and Cancers Flashcards
What are possible causes of thyroid nodules?
adenoma (+/-functioning- often benign), cysts, colloid nodule, abscess, granulomatous dz (TB), developmental abnormalities, carcinoma
How common are nodules?
on PE: 6.4% females and 1.5% in males
up to 37-57% as reported on autopsy
What are the steps in evaluation of a thyroid nodule?
- TSH level - is the nodule causing elevation in TH
- FNA can be used to look at the cellularity of a nodule
- Thyroid scan (if THS is low and FNA shoes follicular neoplasia) can be used to detect cold, warm, hot (rarely malignant) nodules
- thyroid U/S can be useful for sizing nodule and for guiding FNA (cysts are unlikely to be malignant)
- I-131 uptake is used additionally in high TSH to differentiate etiology of hyperthryoidism (never in pregnant patients)
What symptoms would raise suspicion for cancer?
rapid growth hard or fixed masses hoarseness hx or childhood head/neck radiation Fhx of thyroid cancer lymphadenopathy/ distant metastases
What is characteristic of a malignant mass that you would want to biopsy?
nodules >1cm solid, hypo echoic lesions irregular borders central blood flow absence of a halo hx of radiation exposure FH of PTC, MTC or MEN nonfunctioning nodules in the setting of Grave's disease at risk age groups (70)
What are the 4 types of thyroid cancer discussed in the module?
papillary follicular anaplastic medullary (metastatic cancer and lymphoma are also possible but not common)
Describe the histologic presentation of multi-nodular goiter.
enlarged thyroid with nodules separated by thin fibrous bands, variation in follicular size within the nodule
Describe the histologic features of a papillary thyroid carcinoma.
papillary architecture hypercellularity overlapping nuclei cleaved or grooved nuclei (coffee bean appearing nuclear clearing (orphan Annie eyes) intranuclear cytoplasmic inclusions prominent nucleoli psammoma bodies (calcifications at tips of papillary necrosis)
Contrast diagnostic testing for papillary cancer v. follicular cancer.
papillary cancer only requires FNA for diagnosis because of its defining cytologic features
follicular adenoma/carcinoma requires biopsy that preserves tissue architecture to make the diagnosis
Describe the pathologic/histologic features of follicular carcinoma.
may or may not have cytologic atypia (more common at the periphery) but will usually have small follicles within a **thick fibrous capsule, for the diagnosis you must have capsular or vascular invasion
Describe the histology of an anapestic carcinoma.
sheets of cells with marked pleomorphism, numerous (often abnormal) mitoses, necrosis (may have foci of more well differentiated thyroid carcinoma)— mostly high grade and mostly ugly, often expands rapidly on PE
What are the histologic features of a medullary carcinoma (proliferation of C-cells)?
monotonous cells or infiltrative nest of cells which can be plasmacytoid (eccentric nucleus) or spindle shaped; round/oval nuclei with salt & pepper chromatin, amyloid deposition (congo red stain); proliferation shown with calcitonin immunolabeling (arises from C-cell or parafollicular cells
can be associated with c-cell hyperplasia foci (not specific to medullary carcinoma), can be dx with FNA
What treatment is recommended for papillary thyroid v. follicular carcinoma cancer?
papillary: excellent prognosis, typically treated with thyroidectomy, and with more aggressive tumors, I-131 and T4 suppression can be added most commonly contains a BRAF mutation and can metastasize to lymphatics, increased risk with neck irradiation
follicular: prognosis is generally good but depends on the extent of extra thyroidal extension and vascular invasion, it metastasizes hematogenously (Hurtle cell may be more aggressive)
What are poor prognostic features of a papillary thyroid cancer?
tumor size >4cm extra thyroidal extension vascular invasion multifocal tumor bilateral lymph nod metastases Age > 45 tall cell variant, BRAF mutation (MAP kinase pathway)
What is the general prognosis and treatments used in medullary carcinoma?
prognosis varies depending on the extent of the disease at diagnosis, the tumor tends to metastasize early (before palpable exam), common in familial forms (prophylactic thyroidectomy in familial forms with RET screening)
treated with thyroidectomy and followed with calcitonin
