A Case of Acute Myeloid Leukemia with Bone Marrow Basophilia and Dysmegakaryocytic Hyperplasia with Isochromosome 17q as a Sole Cytogenetic Abnormality: A Clinical Study with Literature Review

A new clinico-pathological entity in which isochromosome 17q is the sole abnormality has been reported in myelodysplastic syndrome and in myeloproliferative neoplasm with an aggressive course; In particular, myelodysplastic syndrome with the isolated i(17)(q10) chromosome has the unique features of male sex, severe anemia, dysmegakaryocytic hyperplasia, increased micromegakaryocytes, basophilia, eosinophila and high risk for progression to acute myeloid leukemia (AML). However, the isolated i(17)(q10) is occurring at a relatively low frequency in de novo AML, and only a few reports are available in the literature about the clinical features and molecular characteristics of the isolated i(17)(q10) in AML. Herein, we report both the clinico-pathological features and the results of high resolution single nucleotide polymorphism (SNP) array analysis in a case of AML with i(17)(q10) as the sole cytogenetic abnormality. This case showed marrow findings of basophilia and dysmegakaryocytic hyperplasia and aggressive clinical outcome and these findings were suggestive of the presence of underlying myelodysplastic syndrome. The breakpoint of i(17)(q10) was located within 17p11.2 sub-band, which is known as a genetically highly unstable region presenting a unique genomic architectural features of low copy repeats (LCRs); thus, LCRs within 17p11.2 might lead to genomic instability and facilitate somatic genetic rearrangements such as i(17) (q10) and could play an important pathogenetic role in presenting unique clinico-pathologic features as well as in tumor development and disease progression.

Medulloblastoma: Does the Isochromosome 17q Influence on the Long Term Survival?

OBJECTIVE: An isochromosome for the long arm of 17, i(17q), is the most frequent chromosomal abnormality in medulloblastoma, occurring in 30-60% of cases by karyotype analysis and this abnormality has been reported to be present in cases with a shorter survival time by some authors. Moleculogenetic analysis for i(17q) was performed to identify its influence on the long term survival. PATIENTS AND METHODS:The authors reviewed 17 children and divided them into two groups(favorable and poor outcomes) to elucidate the influence of the i(17q) on the long term survival. Eight children with favorable outcome are in disease-free status during the follow-up period (range: 52-87 months, median: 66 months). The other nine children with poor outcome died of disease progression or recurrence and their median survival time was 13 months (range: 1-28 months). Fluorescent in situ hybridization(FISH) was used for the detection of i(17q) in 17 children. RESULTS: The i(17q) was detected in nine of 17 children. There was no difference in the positive rates of i(17q) between two groups. CONCLUSION: The i(17q) was detected by FISH in 53% of medulloblastoma patients. Presence of the i(17q) was not a prognostic factor on the long term survival.