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 ?
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).
However, the rapid progression in clinical course in a relatively short time, along with the presence of increased megakaryoblasts in bone marrow, prompted a clinical consideration for blast crisis phase of CML, and the patient was managed as evolving into an acute leukemia.
In addition, when there is leukoerythroblastosis in the peripheral blood along with increased fibrosis and increased atypical megakaryocytes and megakaryoblasts, then the differential diagnosis includes acute megakaryoblastic leukemia, acute panmyelosis with myelofibrosis, and transformed primary myelofibrosis.
In addition, many small megakaryoblasts were seen, some indistinguishable from micromegakaryocytes typically seen in CML (Figure 1, a).
a, Bone marrow biopsy with extensive fibrosis (bottom) and clusters of atypical megakaryocytes and megakaryoblasts (middle), admixed with focal areas of myelopoiesis and abundant eosinophils (top).
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.