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Definition / general | Microscopic (histologic) description | Molecular / cytogenetics descriptionCite this page: Mihova D. with hyperdiploidy. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/leukemiaALLhyperdiploidy.html. Accessed December 18th, 2024.
Definition / general
- "High hyperdiploidy" means > 50 chromosomes and < 66 chromosomes without translocations or other structural alternations
- Generally arises by simultaneous gain of all additional chromosomes in a single abnormal mitosis (Genes Chromosomes Cancer 2005;44:113)
- Hyperdiploidy appears to be an early event occurring prenatally (Genes Chromosomes Cancer 2004;40:38, Leukemia 2003;17:2202, Blood 2002;100:347)
- Affects 25 - 33% of children (usually age 3 - 5 years) and 5% of adults with B ALL; not seen in infants
- Favorable overall survival (Am J Hematol 2008;83:34)
- Although outcome in children varies by specific trisomy present (Blood 2003;102:2756)
- Immunophenotype: CD19+, CD10-, CD34+ and CD45-
Microscopic (histologic) description
- No distinct morphology
Molecular / cytogenetics description
- Mutations in NRAS (10%), FLT3 (9%), PTPN11 (9%) and KRAS (6%, Genes Chromosomes Cancer 2008;47:26)
- Most common extra copies are 21, X, 14 and 4; least often 1, 2, 3
- Best prognosis of simultaneous trisomies: 4, 10 and 17
