Aplastic Anemia and Monosomy 7-Associated Dysmegakaryocytopoiesis

Michelle M. Dolan, MD; Timothy P. Singleton, MD; Joseph Neglia, MD, MPH; Adina Cioc, MD


Am J Clin Pathol. 2006;126(6):925-930. 

In This Article

Materials and Methods

Case Definition

We reviewed the hematopathology database of the University of Minnesota Medical Center, Fairview, from January 1993 to December 2005 for pediatric patients (age 18 years and younger) with AA who had cytogenetic analyses performed at this institution. AA was defined as cytopenias due to an inadequate number of hematopoietic cells in the marrow.[18] Patients with Fanconi anemia were excluded. Of 42 patients with AA, 3 had normal cytogenetics followed by acquisition of monosomy 7. The peripheral blood smears and bone marrow biopsy specimens were evaluated for myelodysplastic features before and after development of monosomy 7. The medical records of these patients were reviewed for clinical manifestations, therapy, and outcome.

Hematopathologic Studies

The peripheral blood smears, bone marrow aspirate smears, and touch imprints were air dried and stained with Wright-Giemsa. Bone marrow aspirate slides were stained with Dacie for sideroblastic iron.[19] Bone marrow biopsy specimens were fixed in B-5 or acetic zinc formalin, decalcified, and embedded in paraffin. Then 3-B5m sections were cut and stained with H&E and periodic acid–Schiff. Immunohistochemical analysis was performed on the trephine biopsy specimens for CD61 (2F2, Ventana, Tucson, AZ).

Cytogenetic Analysis

Cells from the bone marrow samples were cultured for 24 to 48 hours according to routine cytogenetic protocols. Chromosome analysis was performed on metaphases G-banded with trypsin and Wright-Giemsa stain. Twenty metaphase cells were analyzed for each patient.

Fluorescence In Situ Hybridization Analysis

Fluorescence in situ hybridization (FISH) was performed using a dual-color probe set to the elastin gene region in band 7q11.23 and loci D7S486 and D7S522 in band 7q31 or a dual-color probe set to D7Z1 and EGFR, mapped to the centromere region of chromosome 7 and to 7p12, respectively (Vysis, Des Plaines, IL). Use of a dual-color probe set decreases the probability of false-positive results, as loss of 1 signal from each locus was required for designation as a monosomy 7 cell. Reference ranges for a monosomy 7 signal pattern in normal control samples is 0% to 1%. FISH was performed according to the manufacturer's instructions. We examined 200 to 400 interphase cells with these probes.


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