Chronic Megakaryocytic Leukemia

What is Chronic Megakaryocytic Leukemia?

Chronic megakaryocytic leukemia belongs to the group of myeloproliferative tumors, this form of leukemia is often not distinguished from the subleukemic myelosis similar to it or is described under the name “hemorrhagic thrombocythemia”, although bleeding is a completely optional sign of this leukemia. Chronic megakaryocytic leukemia is accompanied by hypertrombocytosis in the blood, sometimes 3-4 million in 1 μl. Leukocytosis, a shift of the leukocyte formula to the left, erythrocytosis with this form of myelosis is either not present, or they are weakly expressed. In other words, it is a tumor of a predominantly megakaryocytic germ.

Unlike subleukemic myelosis, chronic myelogenous leukemia with this form of leukemia, there is usually no complete (three-growth) myeloid hyperplasia in the bone marrow, the ratio of fat and bone marrow elements may be normal in case of megakaryocytic germ hype-plasma: in the field of view, more than 5-6 megakaryocytes (normal 12). In chronic megakaryocytic leukemia, the spleen is for the most part slightly enlarged; palpated at the costal margin.

Causes of Chronic Megakaryocytic Leukemia

Chronic megakaryocytic leukemia is a rare disease, information on its prevalence is essentially not provided.

Pathogenesis during Chronic Megakaryocytic Leukemia

In chronic megakaryocytic leukemia, all sprouts of myelopoiesis are clonal. This is evidenced by the results of a study of G-6-FD in female heterozygotes with this disease and a karyological analysis of bone marrow that detected aneuploid clones. However, this did not reveal any specific changes in the karyotype characteristic of chronic megakaryocytic leukemia.

Symptoms of Chronic Megakaryocytic Leukemia

Chronic megakaryocytic leukemia is a form of chronic myeloproliferative leukemia. Some authors tend to consider it as subleukemic myelosis, characterized by a peculiar clinical and hematological symptomatology, others as “hemorrhagic thrombocythemia”, although increased bleeding is not always found in chronic megakaryocytic leukemia.

The approximate formulation of the diagnosis:
Chronic megakaryocytic leukemia with a slightly enlarged spleen, hypertrombocytosis in the blood, the development of thrombosis, nasal and gingival bleeding (platelet aggregation disorders, DIC).

Hypertrombocytosis in the blood, ranging from 700 * 109 / l to 1000 * 109 / l or more (sometimes up to 2000-4000 * 109 / l), is characteristic of chronic megakaryocytic leukemia. Ugly platelets are found in the peripheral blood. Slightly expressed erythrocytosis, leukocytosis with a shift of the leukocyte formula to the left are sometimes noted. In histological preparations of the bone marrow, there is hyperplasia of a megakaryocytic germ (in the field of view more than 5-7 megakaryocytes). The spleen in most cases is not enlarged or barely palpated at the costal margin. Hypertrombocytosis is associated with a tendency to develop thrombosis. The observed often increased bleeding is due to impaired platelet aggregation, DIC.

Diagnosis of Chronic Megakaryocytic Leukemia

Diagnosis is based on a complex of the above clinical and hematological signs. Chronic megakaryocytic leukemia should be differentiated from subleukemic myelosis, which is characterized by splenomegaly with myeloid metaplasia, moderate leukocytosis, neutrophilia, a shift of the leukocyte formula to the left to myelocytes, anemic syndrome, hemorrhages due to thrombocytopenia and hematologic bone marrow failure, hemostosis.

In the diagnosis of reactive thrombocytosis with cirrhosis of the liver with splenic and hepatomegaly, the histological picture of the bone marrow, liver, revealing the presence of myeloid and megakaryocytic infiltration is important; in sepsis and other diseases, the diagnosis of reactive thrombocytosis is based on a set of clinical and laboratory data.

Treatment of Chronic Megakaryocytic Leukemia

With a favorable course of the disease, one should refrain from any special treatment for chronic megakaryocytic leukemia. When signs of thrombosis and erythromelalgia develop, disaggregants, heparin and cytostatic drugs (myelosan or myelobromol in small doses) are prescribed. In the terminal stage, therapeutic tactics are identical to those used for subleukemic myelosis.