Case 74

A 55-year-old male presented with a 3.5 cm thyroid mass.

Question 1:

Which of the following best describes the tumor mutation burden (TMB) of papillary thyroid carcinoma (PTC)?

A) High among all cancer types

B) Moderate among all cancer types

C) Lowest among all cancer types

D) Variable depending on the histologic subtype

Answer

Answer: C) Lowest among all cancer types

Question 2:

Which molecular pathway is most frequently altered in PTC?

A) PI3K/AKT pathway

B) MAPK pathway

C) JAK/STAT pathway

D) WNT/β-catenin pathway

Answer

Answer: B) MAPK pathway

Question 3:

Which of the following mutations is most common in classic PTC and subtypes with papillary architecture?

A) BRAF p.V600E

B) RAS mutations

C) RET fusions

D) TERT promoter mutations

Answer

Answer: A) BRAF p.V600E

Question 4:

Which histologic subtype of PTC has the highest prevalence of BRAF mutations?

A) Follicular variant PTC

B) Tall cell PTC

C) Oncocytic PTC

D) Warthin-like PTC

Answer

Tall cell PTC

Question 5:

Which chromosomal rearrangement is most commonly associated with radiation-induced solid/trabecular PTC (ST-PTC)?

A) CCDC6::RET

B) NCOA4::RET

C) ETV6::NTRK3

D) PPARG::PAX8

Answer

Question 6:

Which molecular alterations are commonly found in spindle cells of PTC with fibromatosis/fasciitis-like stroma?

A) BRAF p.V600E mutations

B) TERT promoter mutations

C) CTNNB1 (β-catenin) mutations

D) KRAS mutations

Answer

Answer: C) CTNNB1 (β-catenin) mutations

Question 7:

What is the estimated prevalence of TERT promoter mutations in PTC?

A) 1%

B) 5%

C) 10%

D) 20%

Answer

Answer: C) 10%

Question 8:

Which RET fusion is the most common in sporadic PTC cases?

A) NCOA4::RET

B) CCDC6::RET

C) ETV6::NTRK3

D) PPARG::RET

Answer

Answer: B) CCDC6::RET

Question 9:

Which molecular alterations are associated with radiation-induced PTC, particularly in children affected by the Chernobyl nuclear accident?

A) BRAF p.V600E mutations

B) TERT promoter mutations

C) NCOA4::RET fusions

D) KRAS mutations

Answer

Answer: C) NCOA4::RET fusions

Question 10:

Which less common mutations and fusions have been reported in PTC?

A) HRAS, KRAS, PPM1D, and CHEK2

B) TP53, RB1, and CDKN2A

C) PTEN, APC, and SMAD4

D) MYC, MDM2, and BRCA1

Answer

Answer: A) HRAS, KRAS, PPM1D, and CHEK2

References: https://tumourclassification.iarc.who.int/chaptercontent/53/44

Case credit: UCSD Pathology

Author: Wangpan Jackson Shi, MD