Differential diagnosis between chronic granulocytic leukemia, polycythaemia vera and essential thrombocythemia using micro-and ultrastructural measurement data performed at the level of megakaryocyte.

The common features of chronic myeloproliferative disorders (CMDs) make the differential diagnosis on clinical or paraclinical basis to become more difficult, and validate the requirements for new methods of detailed diagnosis. Besides the cytogenetic methods, the megakaryocyte (MK) morphology is a valuable element of diagnosis included in the recent "en vogue" criteria. The purpose of this paper is to compare different morphological parameters in MKs from patients diagnosed with three CMDs and to establish a differential diagnosis of these disorders. Studies were performed on smears of bone marrow blood - for light microscope analysis -, and bone marrow biopsies - for transmission electron microscope (TEM) analysis - collected from six patients, two diagnosed with chronic granulocytic leukemia (CGL), two with polycythaemia vera (PV), and other two with essential thrombocythemia (ET). On the light microscope images, we observed important differences between the sizes of MKs and of MKs nuclei in CGL, PV, and ET. On the TEM images, we also noted important differences concerning the size and the aspect of nuclei, aspect of mitochondria, the amount and distribution of RER, Golgi apparatus and demarcation membrane system; the most important are the differences recorded in the number, distribution and sizes of vacuoles, alpha-granules and of the dense bodies. This study provides evidence that there are significant morphological differences between the cellular structures in the MKs from the patients with diagnosed with different CMDs, and thus sustains the utilization of this approach for establishing the differential diagnosis of CMDs.