Thyroid Path

Question 1

Describe an oncocytic cell: histological appearance and function

Answer 1

Metaplastic follicular cell with pink cytoplasm (lots of mitochondria) , round nucleus, round nucleolus

Question 2

Describe the appearance and function of C-cells

Answer 2

C-cells produce calcitonin

Located at lateral aspect of thyroid; rarely seen in regular histology until hyperplastic

Question 3

Factors in histology: enlargement

Answer 3

Diffuse vs. nodular process– is nodule solitary or dominant? capsulated? Smooth or irregular borders?

Question 4

Factors in histology: lesion architecture

Answer 4

Describes cell growth pattern:

Follicles, papillae, solid, trabecular

Question 5

Other features of lesion that are important in thyroid lesion

Answer 5

fibrosis, calcification, amyloid (medullary carcinoma)

Question 6

Describe factors in tumor cell cytology

Answer 6

Cell size
Cytoplasm: indistinct or oncocytic
Nuclear morphology: shape and presence of folds/grooves or inclusions
Nucleoli: prominent; placement in nucleus

Question 7

Which types of enlargement are more likely to be malignant? Benign?

Answer 7

Nodular:
solitary=malignant
multiple=benign
diffuse: benign due to Graves or Hashimoto’s; can rarely be tumors

Question 8

Describe the gross pathology of Grave’s disease (4)

Answer 8

Symmetric and diffuse enlargement of thyroid gland
Red/brown cut surface
Decreased colloid
Increased vascularity

Question 9

Describe the histology of Grave’s disease (2)

Answer 9

Papillary hyperplasia (increased follicles and irregular stroma)
Lymphocytic infiltration in stroma

Question 10

Describe the gross pathology of Hashimoto’s thyroiditis: (2)

Answer 10

diffusely enlarged gland

Lobulated cut surface (white)

Question 11

Describe the histological appearance of Hashimoto’s thyroiditis (3)

Answer 11

Follicular atrophy
Lymphocytic infiltration throughout gland
Oncocytic metaplasia

Question 12

Prevalence of thyroid nodules

Answer 12

4-7% of US population

Question 13

What are the types of non-toxic nodular goiter? (4)

Answer 13

Endemic goiter (iodine deficiency)
Sporadic goiter
Chemically induced goiter
Dyshormonogenetic goiter

Question 14

Gross pathology of non-toxic nodular goiter (big list)

Answer 14

Heterogenous: Firm, diffusely enlarged
Cut surface is shiny and amber---increased colloid accumulation
Asymmetric enlargement
Multinodular
Hemorrhage
Calcification 
Fibrosis
Cystic degeneration

Question 15

Describe the histological appearance of non-toxic nodular goiter

Answer 15

Variable sized follicles with columnar epithelium that can be tall or flattened
Papillary hyperplasia
Fibrosis (follicles outgrow blood supply)

Question 16

Describe the gross appearance of a follicular adenoma (3)

Answer 16

Solitary

Well circumscribed/encapsulated

Question 17

Histological appearance of follicular adenoma (3)

Answer 17

Encapsulated nodule
Follicular, solid, trabecular growth pattern
No invasion

Question 18

What is the epidemiology of malignant epithelial tumors of thyroid?

Answer 18

Uncommon– 1-2% of all cancers

More common in females

Question 19

How do most thyroid tumors behave?

Answer 19

indolent

Question 20

What is pathogenesis of follicular cell

Answer 20

irradiation during childhood– causes papillary carcinoma due to ret oncogene rearrangements

Question 21

What are mutations of thyroid neoplasms? (5)

Answer 21

Ret/PTC rearrangement
RAS
BRAF
p53
Adenomatous polyposis coli gene (APC)

Question 22

Describe RET/PTC rearrangement.

In which thyroid malignancy is this seen?

Answer 22

Inversion on chromosome 10 leads to over activation of tyrosine kinase of Ret

Seen in 60-80% of papillary thyroid carcinomas, especially due to irradiation

Question 23

What is cell of origin in epithelial neoplasms? What do they produce?

What are the two epithelial neoplasms?

Answer 23

Follicular cells, which produce thyroglobulin

Neoplasms are follicular cell carcinoma and papillary thyroid carcinoma

Question 24

Describe the epidemiology of papillary thyroid carcinoma

Answer 24

Most common type of thyroid cancer: 80% of thyroid cancers in non-endemic goiter regions

More common in women

Question 25

What are the pathological features for diagnosis in papillary thyroid carcinoma? Nucleus

Answer 25

Nuclear features: elongation, chromatin clearing, membrane thickening, grooves and inclusions

Question 26

What are the growth patterns of papillary thyroid carcinomas?

Answer 26

``` Papillary formations (core with stuff around) Follicular variant-- colloid Tall cells ```

Question 27

What is gross pathology of papillary thyroid carcinoma?

Answer 27

Cystic with mound of tumor cells

Question 28

Describe the clinical behavior of papillary thyroid carcinoma?

Answer 28

Aggressive-- older age, male, large size, tall cell variant, distant metastases

Question 29

Describe the epidemiology of follicular carcinoma

Answer 29

5% of all thyroid carcinomas in US Incidence increase with age Common in iodide deficient regions

Question 30

Describe important features of follicular carcinoma (3)

Answer 30

Encapsulated tumor that invades Hematogenous spread to brain, lungs and bone Prognosis is dependent upon extent of invasion

Question 31

Describe the histological pathology of follicular carcinoma

Answer 31

Capsular but with vascular invasion. All about vascular invasion

Question 32

Name differences between papillary carcinoma and follicular carcinoma (3)

Answer 32

1. Diagnosis based on nuclear morphology vs. vascular invasion 2. Spread via lymphatics vs. blood vessels 3. Presentation as multiple tumors vs. single tumor nodule

Question 33

From which cell type does medullary carcinoma originate? What are causes? (2)

Answer 33

Originates from C-cells so produces calcitonin It can arise from MEN2 disorders or be sporadic

Question 34

What is the pathogenesis of medullary carcinoma (what mutation is involved?) What is prognosis?

Answer 34

Germ line mutation of ret-oncogene Secretes calcitonin, other hormones Prognosis is 50% at 5 years

Question 35

Describe the histological appearance of medullary carcinoma? (2)

Answer 35

Nest-like pattern (since its neuroendocrine--think theochromyocytomas!) Stains for amyloid and calcitonin

Question 36

What is the prognosis for anaplastic carcinoma? Which patients are more likely to get this?

Answer 36

Prognosis: fatal-- invade into surrounding neck structures | Constitutes 5% all thyroid malignancies

Question 37

What is epidemiology of anaplastic carcinoma? What is anapestic carcinoma usually preceded by?

Answer 37

Women>60 years of age Preceded by a history of goiter Can also result from de-differentiation of other thyroid malignancy

Question 38

Describe the histological appearance of anaplastic carcinoma . What does it stain for?

Answer 38

Pleomorphic tumor cells-- spindle cells and multinucleated giant cells Does not stain for thyroglobulin, calcitonin