thyroid 4 Flashcards
most thyroid neoplasms present as
solitary nodules as incidental findings
ddx is between colloid nodule, adenoma and carcinoma
most thyroid neoplasms
non functional - don’t produce hormones
less than 1% of solitary thyroid nodules are malignant - still many cases because they’re common
most thyroid cancers are indolent - low stage follicular and papillary - 90% 20 year survival
clues to the nature of a thyroid nodule
- solitary are more likely neoplastic
- nodules in younger patients more likely neoplastic, but more likely better prognosis
- nodules in males more neoplastic
- radiation exposure history more neoplastic
- nodules taking up radioactive iodine more likely benign than malignant
nodules that take up radioactive iodine
hot nodules
more likely to be benign than malignant
history of radiation exposure is associated with
increased incidence of thyroid malignant
adenomas
benign epithelial tumours
follicular adenoma
hurthle cell adenoma
carcinomas
malignant epithelial tumours
follicular
papillary - common
anaplastic - undifferentiated
medullary - nueroendocrine - carcinoma
adenoma
- most are follicular, hurthle cell less common
- solitary nodule
- well circumscribed
- encapsulated
- usually normal background thyroid
- important - no capsular invasion, extra thyroidal extension or lymph-vascular invasion
- usually non functional, euthyroid
- may cause hyperthyroidism
- treatment is hemithyroidectomy
adenoma nodule
encapsulated and well circumscribed solitary nodule
follicular carcinoma
- similar radiological appearance and presentation to follicular adenoma
- solitary nodule, well or poorly circumscribed
- thickly encapsulated
- capsular invasion, extra-thyroidal extension or lymph-vascular invasion
- minimally invasive = good prognosis, widely invasive = bad prognosis
- majority are non functional
- may metastasise late by haematogenous spread to bone, lungs, liver
papillary carcinoma
most common in thyroid cancer
often young women
strong association with ionising radiation
often multifocal - treatment is total thyroidectomy
forms papillae, with crowded cells demonstrating nuclear grooves and clear chromatin, often psammomatous calcification and fibrosis - not encapsulated
lyphatic invasion is common
underlying RET/PTC and BRAF mutations - activate MAPK pathway
good prognosis
prognosis papillary carcinoma
good in young, slightly worse in older
how many foci in papillary carcinoma
ofter multifocal - treatment is total thyroidectomy
papillary carcinoma forms
papillae, with crowded cells demonstrating nuclear grooves and clear chromatin - not encapsulated
anaplastic carcinoma
rare
older patients
often preceded by follicular or papillary thyroid carcinoma
agressive, rapidly enlarging and infiltrative neck mass with mass effect, hoarseness
often metastatic at time of presentation
often multifocal needing thyroidectomy
lymphatic invasion is common to central neck nodes
