Myelodysplastic syndrome with atypical eosinophilia in association with ring chromosome 7. A case report.

The presence of morphologically abnormal eosinophils in the bone marrow and/or peripheral blood has been rarely reported as a prominent feature in myelodysplastic syndromes (MDS). Specific chromosomal aberrations have been observed in such cases. We report a case of a 76-year-old man who presented with chronic, transfusion-dependent anemia. Peripheral blood smear analysis revealed anisocytes, mild leukopenia, and occasional hypersegmented eosinophils. A subsequent bone marrow biopsy and aspiration disclosed hypercellularity, and morphologic abnormalities within the megakaryocyte, erythroid, and myeloid series. The myeloid population was predominantly comprised of eosinophils with varying degrees of dyspoiesis. The constellation of hematologic findings were without a precise categorization according to the FAB classification of myelodysplastic syndromes. Subsequent cytogenetic techniques demonstrated a ring chromosome 7 in all 20 metaphases analyzed in cultured bone marrow cells. Eighty-five-percent of the analyzed cells showed a ring chromosome composed of both the long and short arms: r(7)(p22q36). In the remaining metaphases, the ring was composed of only the short arm: r(7)(p22q10). To our knowledge, these uncommon cytogenetic abnormalities have not been previously reported in association with MDS with morphologically atypical bone marrow or peripheral eosinophilia.