Repeat bone marrow biopsy and aspirate (Figure 1(a)) showed 64% myeloblasts
which expressed a slightly different immunophenotype than originally (CD13, CD33, CD15, CD58, CD117, and HLA-DR).
Panels (c) and (d) show confluent immature myeloblasts
consistent with myeloid sarcoma.
Bone destruction is attributed to the invasion of leukemic myeloblasts
or an imbalance of osteoblasts and osteoclasts.
They also found that such artificially created elite cells are very similar to white blood cell progenitors in the bone marrow called GMPs or myeloblasts
, which themselves require C/EBPa for their formation.
Promyelocytes and myeloblasts
are not observed (Wright stain, 1000x).
The first, also called erythroleukemia, involves myeloblasts
and rubriblasts (BENNETT et al., 1976).
Myeloid sarcoma, also known as chloroma, extramedullary myeloid tumor or granulocytic sarcoma, is an extramedullary tumor mass consisting of immature myeloid cells and/or myeloblasts
. (1,2) Myeloid sarcoma can occur de novo, concurrently or following the diagnosis of acute myeloid leukemias (AML), myeloproliferative neoplasms (MPN), and myelodysplastic syndromes (MDS).
Bone marrow aspiration revealed hypercellularity, different cell body sizes, diminished or moderate cytoplasms, round or oval nuclei, enhanced nuclear chromatin, and 10% myeloblasts
. Differential flow cytometric analysis demonstrated that the blasts expressed the myeloid antigens CD34, CD13, and CD117.
Visual examination of spleen sections revealed that splenocytes from NOD mice had a tendency to ring-shaped rather than polylobed morphology, indicating presence of granulopoietic stage 1 myeloblasts
. C57BL/6 mice had a population of cells displaying the more polylobed morphology, of more mature neutrophils (Figure 5), indicating that relatively more immature granulocytes are present in the spleen and liver of NOD mice.
[sup], Increased production of cytokines and expression of adhesion markers such as intercellular adhesion molecule-1, vascular cell adhesion molecule-1, and selectin by endothelial cells enables myeloblasts
to recruit additional myeloblasts
One case of AML, however, showed pancytopenia with presence of myeloblasts
in the peripheral blood.