thyroid pathology

Question 1

thyroid inflammations

Answer 1

many types- infectious thyroiditis (tuburculosis)
Subacute granulomatous (de Quervain) thyroiditis
Chronic lymphocytic (hashimoto) thyroiditis
Fibrosing (Riedel) thyroiditis

Question 2

Hashimoto thyroiditis

Answer 2

Autoimmune- Anti-TPO, anti Tg
Diffuse enlargement
Microscopic- lymphocytic inflammation, germinal centers, hurthle cell change (metaplasia)

Question 3

Subacute thyroiditis (de Quervain)

Answer 3

Viral or post viral response, painful, self limited disease, microcytic appearance

Suppurative (PMNs), granulomas (giant cells)

Question 4

Fibrous Riedel thyroiditis

Answer 4

hard and fixed thyroid, painless, microscopic appearance, dense fibrosis (collagen fibers), fibrosis can extend outside of the thyroid

Question 5

Thyroid hyperplasia - graves

Answer 5

Autoimmune- diffuse involvement
Most common cause of endogenous hyperthyroidism
microscopic appearance - irregular follicles, scalloped colloid

Question 6

histology of goiter aka nodular hyperplasia

Answer 6

follicles lined by crowded columnar cells, variable sized follicles, abundant colloid, initial stages result in symmetrical, diffuse enlargement

Recurrent episodes lead to a multinodular gland

with time eill develop degenerative changes (cysts, fibrosis, calcification, hemorrhage)

Question 7

solitary palpable thyroid nodules

Answer 7

incidence in US is between 1 and 10%, 4 times more common in women, majority are non- neoplastic (focal hyperplasia, simple cyst), or benign (adenomas)

Carcinoma is relatively uncommon (< 1% of all solitary thyroid nodules)

Fine needle aspiration- quick diagnositic for paipllaty carcinoma, medullary carcinoms

Question 8

Follicular adenoma

Answer 8

benign neoplasm, various morphologic appearances (follicular, microfollicular, trabecular, hurthle cell)
not clinically significant

Most are nonfunctional

Doesnt progress to carcinoma

Functional adenomas (toxic adenomas) produce thyrotoxicosis

Solitary, completely surrounded by a fibrous capsule, no capsular or vascular invasion, different growth pattern from adjacent normal gland

follicular carcinoma invades thru the capsule

looks like a small cells sheet

Question 9

thyroid carcinoma

Answer 9

uncommon and low mortality, more commen in women, occurs in all ages including kids, most significant risk factor is development of thyroid cancer is exposure to ionizing radiation
4 main types with follicular being the vast majority
Follicular- ras oncogene
Papillary- braf oncogene
Medullary-ret
Anaplastic- p53

Question 10

Papillary thyroid cancer

Answer 10

most common form of thyroid cancer, most occur in youngens, preferentially metastasize by way of lymphatics to regional lymph nodes, cervical nodes involved in up to 50% of cases, excellent prognosis, adverse prognostic factors, 40s, tumor 5 cm. extra thyroidal extension, and osseous mets

Papillary architecture, chewing gum colloid, psammoma bodies, multinucleated giant cells, nuclear features are the key (clear nuclear nuclei orphan annie, intranuclear cytoplasmic inclusions, intranuclear grooves)

Question 11

follicular thyroid carcinoma

Answer 11

presents at an older age than papillary (40s and 50s), slowly enlarging painless nodule vascular spread to bone, lungs liver

Prognosis depends on stage at presentation,

Criteria for diagnosis: no cytologic features of malignancy (no atypia, mitosis, nuclear pleomorphism)

most tumors are well differentiated

CAPSULAR INVASION, VASCULAR INVASION

Minimally invasive carcinomas are difficult to distinguish from follicular adenomas and extensive sampling of the capsule is required

Question 12

medullary carcinoma

Answer 12

neuroendocrine tumors derived from parafollicular c- cells of the thyroid
tumors secrete calcitonin 80% are sporadic, 20% occur as part of the MEN2 syndrome
40-50s except MEN2- kids
40-60% survival at 10 yrs

nests of neuroendocrine cells, amyloid stroma

Calcitonin+, chromogranin, synaptophysin, CEA+ keratin + thyroglobulin -

Question 13

Anaplastic carcinom

Answer 13

undifferentiated tumors of follicular epithelium (does not stain with thyroid specific immunostains)
Mean age at presentation is 65 years, may have a history of long standing goiter, differentiated thyroid carcinoma or concurrent papillary carcinoma, most have extrathryroidal spread or distant metastasis at presentation (hoarsness and neck pain
Mortality rate is 100% :(
mean survival is 6 months, microscopic appearance Variable cell types (spindle cells, epitheliod cells, giant cells, all cells are pleomorphic