Complex structural and numerical abnormalities in myelodysplastic/myeloproliferative disorders
Myelodysplastic/myeloproliferative (MDS/MPD) diseases, classified among atypical chronic myeloproliferative disorders, exhibits both dysplastic and proliferative features at the time of first presentation.
We selected three MDS/MPD cases investigated in our laboratory, displaying complex abnormalities of cellular genome.
Bone marrow chromosomal studies were performed by classical cytogenetic procedures and FISH painting.
In the first case, structural rearrangements were identified: translocation t(6;14)(q21;q32), and a genomic instability with the presence of double minutes and chromosome breaks.
In the second case, chromosomal studies revealed both numerical and structural anomalies. Modal chromosome number was 51 (48-51). Hyperdiploidy resulted from trisomy 1, 14, 21 and the presence of 2-3 supernumerary markers similar to C group. Structural rearrangements of autosomes 1 and 19 were observed.
The karyotype of the third case was hypodiploid with 44-45 chromosomes in 92% of bone marrow cells. At least four markers were observed in hypodiploid cells. FISH with WCP 5 and 3 DNA probes allowed the identification of chromosome 5 fragments located on three different markers.
MDS/MPD category represents a challenge due to difficulties in diagnosis and poor prognosis. The cases presented in this paper confirm once more the problems raised by these atypical malignant proliferations.