Isolated isochromosome 17q: a distinct type of mixed myeloproliferative disorder/myelodysplastic syndrome with an aggressive clinical course.
A clinicopathologic study was performed on 15 patients with haematological malignancies in which isochromosome 17q [i(17q)] was the sole structural chromosome abnormality identified in bone marrow. The data indicated that an isolated i(17q) is associated with a distinct type of mixed chronic myeloproliferative/myelodysplastic disorder with an aggressive clinical course. The patients ranged in age from 37 to 83 years (median 60) with a M:F ratio of 3:1. All cases were chronic myeloid disorders with mixed proliferative and dysplastic features, making classification difficult. 11 patients tested for BCR/ABL gene fusion were normal. A low bone marrow blast count (<5%) at presentation was a typical finding. All cases had severe myeloid dysplasia which included non-segmented neutrophils and an increase in the monocyte/macrophage lineage. Fluorescence in situ hybridization (FISH) analysis of one case showed the i(17q) to involve all myeloid lineages, but not the lymphocytes. For cases with complete follow-up (n = 11) the median survival was 2.5 years (range 0.83-5.25) and 64% progressed to AML prior to death. The following features were identified which defined the haematological disorder associated with an isolated i(17q): (1) adult patient, (2) chronic myeloid disorder with clonal involvement of all myeloid lineages, (3) mixed chronic myeloproliferative/myelodysplastic features, (4) severe hyposegmentation of neutrophil nuclei, (5) prominence of the monocyte/macrophage lineage, (6) high risk for progression to AML, and (7) median survival of 2.5 years.
McClure
R F
RF
Division of Haematopathology, Mayo Clinic, Rochester, Minnesota, USA.
Dewald
G W
GW
Hoyer
J D
JD
Hanson
C A
CA
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002886:Chromosomes, Human, Pair 17 / Q000235:genetics*; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D018404:Isochromosomes / Q000235:genetics*; D007621:Karyotyping; D008297:Male; D008875:Middle Aged; D009190:Myelodysplastic Syndromes / Q000235:genetics*; D009196:Myeloproliferative Disorders / Q000235:genetics*