Thyroid

Question 1

BRAF in thyroid PTCs

Answer 1

Point mutation in BRAF in 45%.

Asso with poor prognostic factors

Question 2

Hurtle cell N VS medullary T Ca

Answer 2

HCN: thyroglobulin + calcitonin -

Med thy ca: thyroglobulin- calcitonin + chromogranin+
Amyloid in 80%

Question 3

Mutations

Answer 3

Point mutation in RAS- 40-50% of follicular ca as well as 10-20% of PTCs follicular variant.
HRAS and KRAS - med thyroid ca

RET/PTC1 and RET/PTC3 —- 10-20% of PTCs( children, radiation history)

RET gene- med TC

PAX8/PPARy- 30-40% follicular Ca (also low in foll v PTCs and follicular adenoma)

Question 4

Most common mutation seen in non-invasive follicular thyroid neoplasm with papillary like nuclear features (NIFTP) ?

Answer 4

RAS

Question 5

Syndromes and thyroid tumors

Answer 5

PTEN mutations - Cowden Syndrome = follicular thyroid carcinoma

FAP syndrome (APC gene)= cribriform morular var of PTC

MEN 2A and MEN 2B = medullary carcinoma

WRN gene - anaplastic carcinoma and Werner syndrome

Question 6

Aggressive types of PTC

Answer 6

Tall cell variant
Columnar cell variant
Diffuse sclerosing variant
Solid variant
PTC with prominent hobnail features

Question 7

HLA and thyroid lesions

Answer 7

HLA- B8: Graves’ disease

HLA- DR3/DR4/DR5 - Hashimoto’s thyroiditis

HLA Bw35 - Subacute thyroiditis

Question 8

Hyalinizing trabecular tumor - unique IHC

Answer 8

Ki-67 in a membranous pattern