Different morphology of megakaryocytes to help and guide to diagnosis

 

Normal megakaryocytes features:

Normal megakaryocytes:
Strongly multi-lobulated nucleus with irregular lobes, connected with chromatin threads, with a clumped chromatin structure. Cytoplasma can be anything from basophilic to pink and can contain from none to abundant azurophilic granules


Myelodysplastic features (MDS):

Micromegakaryocytes:
mononuclear cell
12-40 µm diameter, sometimes bilobulated, dense chromatin with high nucleas to cytoplasm ratio. Cytoplasm is moderately mature
Hypolobulation:
normal sized megakaryocyte with hypo- or non-lobulated nucleus,
rond to oval shaped, normal chromatin condensation and normal cytoplasm structure.
Multilobulation:
normal to large megakaryocyte with multiple separate nuclei,
usually rond, normal to dense chromatin condensation and normal cytoplasm structure.


Features with different Myeloproliferative disorders (MPN):

CML:
Increased number of smaller megakaryocytes and sometimes hypolobulated.
PV:
Increased number of morphologically normal megakaryocytes, in all different maturation stages. Often clustering.
ET:
Many megakaryocyten in normocellulair bonemarrow, with bizarre giant megakaryocytes, with abundant cytoplasm and hyperlobulated nucleus (stag-horn shaped) and clumped chromatin.


Cells that may mimic megakaryocytes

Osteoclasts:
Large cells, have multinucleated, well-separated and uniformly sized round to ovoid nuclei.
Plasmacells:
Multilobulated giant plasmacells
Morbus Hodgkin:
Hodgkin cells: large multilobulated nucleus with coarse chromatin, multiple bluish nucleoli, abundant slightly basophilic cytoplasm.