Anatomy of Hematologic System Related

Review Anatomy of Hematologic System related questions and content

A 5-year-old boy presents with a 3-week history of his right eye “not moving to the right side.” The remainder of his neurologic exam is normal with the exception of a weak gag. MRI of the brain reveals a diffusely infiltrative mass in the pons. If this patient were to undergo a stereotactic biopsy, what would be the most likely molecular finding?

  • A. BRAFKIAA1549 fusion
  • B. Trisomy 21
  • C. H3 K27M mutation
  • D. RELA fusion
Correct Answer: C

Rationale: The correct answer is C: H3 K27M mutation. In children with diffuse midline gliomas, the most common molecular finding is the H3 K27M mutation. This mutation is associated with a worse prognosis and is commonly found in tumors located in the pons, which is consistent with the MRI findings in this case.
Choice A (BRAFKIAA1549 fusion) is incorrect as this fusion is typically associated with pilocytic astrocytomas, which are low-grade tumors and not typically found in the pons.
Choice B (Trisomy 21) is incorrect as it is a chromosomal abnormality associated with Down syndrome, not a molecular finding in brain tumors.
Choice D (RELA fusion) is incorrect as this fusion is typically found in ependymomas, which are not typically located in the pons.