Micromegakaryocytes in Human Bone Marrow.

Micromegakaryocytes (MMK) were defined morphologically by the cell area, nucleus form and cytoplasmic structure. Bone marrow smears of 7,156 patients were retrospectively analyzed. MMK were found most frequently and abundantly in acute non-lymphatic leukaemia, chronic myeloid leukaemia and pre-leukaemia. The presence of more than 10% MMK in the megakaryocyte population suggest a pre-leukaemic condition or non-lymphatic leukaemia. The platelet production of MMK is probably quantitatively normal although a functional defect is suspected.