megakaryoblast


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megakaryoblast

 [meg″ah-kar´e-o-blast″]
the earliest cytologically identifiable precursor in the thrombocytic series, which matures to form the promegakaryocyte.

meg·a·kar·y·o·blast

(meg'ă-kar'ē-ō-blast'),
The precursor of a megakaryocyte.
Synonym(s): megacaryoblast

megakaryoblast

/mega·karyo·blast/ (-kar´e-o-blast″) the earliest cytologically identifiable precursor in the thrombocytic series, which matures to form the promegakaryocyte.megakaryoblas´tic

megakaryoblast

The most immature cell of the megakaryocytic series, which is round or ovoid, and large but variably sized (7–35 µm in diameter; those measuring < 15 µm are termed micromegakaryoblasts). The nuclei are round or oval, contain 1+ nucleoli and have a coarse granular pattern; cytoplasm is scant, blue, agranular, often rims the nucleus, occasionally with several small, blunt, budding peripheral protrusions. Megakaryoblasts are normally found only in the marrow, but may be seen in blood smears with myeloproliferative disorders, especially postsplenectomy.

meg·a·kar·y·o·blast

(meg'ă-kar'ē-ō-blast)
The precursor of a megakaryocyte.

megakaryoblast

the earliest cytologically identifiable precursor in the thrombocytic series, which matures to form the promegakaryocyte.
References in periodicals archive ?
myeloblast, monoblast, erythroblast and megakaryoblast that accumulate in the marrow and interfere with production of blood cells.
A case report by Pelloso et al5 of a 25-year-old woman who presented with findings suggestive of leukemia raised a differential diagnosis of acute megakaryocytic leukemia with t(9;22)(q34;11) and megakaryoblast crisis as first-time presentation of CML.
A bone marrow biopsy was performed; the aspirate was unsuccessful ("dry tap") but the biopsy material showed a fibrotic bone marrow with atypical megakaryocytes and megakaryoblasts (Figure 1, a).
The megakaryoblasts were markedly reduced with reactive plasmacytosis.
The "preleukemic" phase manifests at, or soon after, birth with circulating megakaryoblasts that are clonal in origin.
6,7,11) At the other end of the disease spectrum, neonatal (or even fetal) demise occurs in approximately 10% of patients secondary to diffuse organ infiltration by megakaryoblasts, associated parenchymal fibrosis, and subsequent multisystem failure.
The peripheral blood and bone marrow blasts in TAM have basophilic cytoplasm with cytoplasmic blebbing, suggestive of megakaryoblasts.
The spectrum of blasts in TAM ranges from myeloid (typically lacking Auer rods), megakaryoblasts (being more abundant) and erythroblasts.
Blasts refer to myeloblasts, lymphoblasts, monoblasts, promonocytes, and megakaryoblasts.
2) Interestingly, these megakaryoblasts also have features of early erythroid precursors, appearing to be a precursor cell with biphenotypic properties.
The phenotypic profile of the megakaryoblasts (Table) aid in ruling out the following differential diagnostic concerns.