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Flashcards in Thyroid Path Deck (38):
1

Describe an oncocytic cell: histological appearance and function

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

2

Describe the appearance and function of C-cells

C-cells produce calcitonin

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

3

Factors in histology: enlargement

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

4

Factors in histology: lesion architecture

Describes cell growth pattern:
Follicles, papillae, solid, trabecular

5

Other features of lesion that are important in thyroid lesion

fibrosis, calcification, amyloid (medullary carcinoma)

6

Describe factors in tumor cell cytology

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

7

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

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

8

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

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

9

Describe the histology of Grave's disease (2)

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

10

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

diffusely enlarged gland
Lobulated cut surface (white)

11

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

Follicular atrophy
Lymphocytic infiltration throughout gland
Oncocytic metaplasia

12

Prevalence of thyroid nodules

4-7% of US population

13

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

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

14

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

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

15

Describe the histological appearance of non-toxic nodular goiter

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

16

Describe the gross appearance of a follicular adenoma (3)

Solitary
Well circumscribed/encapsulated

17

Histological appearance of follicular adenoma (3)

Encapsulated nodule
Follicular, solid, trabecular growth pattern
No invasion

18

What is the epidemiology of malignant epithelial tumors of thyroid?

Uncommon-- 1-2% of all cancers
More common in females

19

How do most thyroid tumors behave?

indolent

20

What is pathogenesis of follicular cell

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

21

What are mutations of thyroid neoplasms? (5)

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

22

Describe RET/PTC rearrangement.

In which thyroid malignancy is this seen?

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

23

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

What are the two epithelial neoplasms?

Follicular cells, which produce thyroglobulin

Neoplasms are follicular cell carcinoma and papillary thyroid carcinoma

24

Describe the epidemiology of papillary thyroid carcinoma

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

More common in women

25

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

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

26

What are the growth patterns of papillary thyroid carcinomas?

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

27

What is gross pathology of papillary thyroid carcinoma?

Cystic with mound of tumor cells

28

Describe the clinical behavior of papillary thyroid carcinoma?

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

29

Describe the epidemiology of follicular carcinoma

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

30

Describe important features of follicular carcinoma (3)

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

31

Describe the histological pathology of follicular carcinoma

Capsular but with vascular invasion. All about vascular invasion

32

Name differences between papillary carcinoma and follicular carcinoma (3)

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

33

From which cell type does medullary carcinoma originate?

What are causes? (2)

Originates from C-cells so produces calcitonin

It can arise from MEN2 disorders or be sporadic

34

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

What is prognosis?

Germ line mutation of ret-oncogene
Secretes calcitonin, other hormones

Prognosis is 50% at 5 years

35

Describe the histological appearance of medullary carcinoma? (2)

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

36

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

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

37

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

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

38

Describe the histological appearance of anaplastic carcinoma .

What does it stain for?

Pleomorphic tumor cells-- spindle cells and multinucleated giant cells

Does not stain for thyroglobulin, calcitonin