Description:

Cell oval or round shape, usually larger than the myeloblast.

Size:

20-25 µm.

Cytoplasm:

Slightly more abundant than in the myeloblast, clear blue, and the color intensity diminishes towards the center of the cell.
The cytoplasm contains two types of granules:              

• primary azurophilic granules, red colored; and
• secondary granules, bright brown, 0.2-10.9 µm in diameter.

Primary granules are spherical, rich with acid phosphatase, peroxydase, esterases, N-acetyl-b-glucosoaminidase and lysosime. They do not contain alkaline phosphatase.

Nucleus:

A large, oval or round, sometimes with a slight concave depression. The chromatin begins to condense in some parts of the nucleus without forming compact chromatin. The chromatic strands are somewhat coarser than in the myeloblast.

Nucleoli

Can be rarely found.