Individual Forms of Leukemia

What are Individual Forms of Leukemia?

The two leukemia described above have histochemical differences; however, their morphology and clinical picture are almost the same. Myelomonoblastic acute leukemia can be represented by cells, each of which has histochemical signs of both monocytic and granulocytic series; At the same time, there are cases when some of the blast cells belong to myeloblasts, and some to monoblasts.

This group of leukemia is often combined in the literature with the concept of “non-lymphoblastic” leukemia, along with promyelocytic, monoblastic leukemia and erythromyelosis.

Among non-lymphoblastic acute leukemia in adults, myeloblastic and myelomonoblastic forms account for about 80-90%, and all non-lymphoblastic acute leukemia in adults account for about 85% of all acute leukemia. In children, about 85% are acute lymphoblastic leukemia.

Myeloblastic and myelomonoblastic leukemia are distinguished.

According to the cardiological criterion, the form of myelomonoblastic acute leukemia with high eosinophilia in the blood or only in the bone marrow was also isolated. In almost 100% of cases, patients with this form of leukemia have an inversion of the chromosome of the 16th pair (Yunis, 1983).

In myelomonoblastic form, another special variant is currently identified, similar to acute promyelocytic leukemia in morphology of atypical cells and in DIC. The cytochemical characteristic of cells, despite the abundant azurophilic granularity, corresponds to an acute myelomonoblastic form. The cells of this leukemia do not contain acid sulfated mucopolysaccharides characteristic of promyelocytic leukemia. Bone marrow fibroblasts with this form of myelomonoblastic leukemia, in contrast to promyelocytic leukemia, grow well in a monolayer culture. Therapy for acute myelomonoblastic leukemia should be the same as promyelocytic acute leukemia.

The clinical picture of acute myeloblastic and myelomonoblastic leukemia is usually caused by hematological disorders. A severe onset of the disease with high fever, necrosis in the throat is characteristic of cases with deep primary granulocytopenia (less than 750-500 granulocytes in 1 μl of blood).

In adults, as a rule, with leukemia, initially there is no increase in lymph nodes, liver, and spleen. In children, extramedullary lesions are somewhat more common. In contrast, with congenital forms of these leukemia, organ and skin lesions are quite common.

Neuroleukemia is rarely at the onset of the disease, but if its prevention is not carried out, it is observed in about a quarter of cases with both improvements and exacerbations.

The increase in spleen in acute myeloid and myelomonoblastic leukemia is moderate; often with myeloid leukemia at first, the spleen is not palpable, but only with exacerbation it is sometimes determined in the depths of the hypochondrium. Usually, an enlargement of the spleen coincides with other signs: the withdrawal of leukemia from the control of previously effective cytostatic drugs, significant inhibition of normal hematopoiesis sprouts. In some cases, there is a sharp increase in the spleen, it reaches the level of the navel. The liver usually does not enlarge, although, as a rule, there is an infiltration of its parenchyma by leukemia cells.

In acute myeloid leukemia, tumor damage to the lungs is observed in 35% of cases, a similar picture occurs in other forms of acute leukemia, although, as a rule, this lesion develops in the terminal stage.

Relapse of such leukemia is caused by various signs: against the background of successfully supporting treatment, cytopenia increases and blast cells appear in the peripheral blood, as well as extramedullary growth foci that determine the corresponding clinical picture. Such patients during the improvement period should remain under continuous hematological control with the obligatory blood test at least 3 times a month and bone marrow at least 1 time in 1-3 months.

Death with this disease can occur at any stage of the process. A frequent cause of death of patients is blood poisoning with toxins secreted by bacteria, as well as other infectious complications caused by cytostatic agranulocytosis, hemorrhages, characterized by deep thrombocytopenia. In children, these forms can be milder than in adults, sometimes it is possible to get an improvement.

Diagnosis of Individual Forms of Leukemia

The hematological picture at the time of diagnosing the process can be different: moderate anemia of normal or slightly hyperchromic type, leukocytosis with blasts in the blood or leukopenia with or without blasts, normal platelet count or thrombocytopenia of varying severity. In some cases, this form of acute leukemia can begin with the already described so-called pre-leukemic stage: partial cytopenia or pancytopenia, prolonged absence of blast cells in the blood and their low content in the bone marrow.

In myeloblastic and myelomonoblastic leukemia, blast cells contain azurophilic granularity in the cytoplasm, which are often clearly visible in a light and electron microscope of Auer bodies, which are a prognostically favorable sign.

Auer bodies in acute myeloid leukemia, as a rule, are expressed by tubular structures oriented linearly, and much less often by granular formations. With electron microscopy, you can see the transitional forms from azurophilic granules to Auer bodies containing lysosomal enzymes: acid phosphatase and peroxidase. The presence of granules in the cytoplasm of myeloblasts in some cases can only be detected cytochemically. The shape of the nucleus of blast cells is usually round, sometimes with a slight impression or irregular, but the ratio of the nucleus to the cytoplasm is always in favor of the nucleus.

During the disease, blast cells of the described form of leukemia undergo regular changes: the nucleus becomes not round, but irregular, the cytoplasm from the narrow rim becomes wide and the cells acquire irregular shapes instead of round ones. Granularity, which is found at the beginning of the disease in a large percentage of cells, in many of them becomes invisible during exacerbation, the reaction to peroxidase in myeloblasts at this stage is also often negative, whereas at the beginning of the disease it is positive in most cases, even in myeloblasts without granularity.

The prognosis of the disease is determined by the age of the patient and whether or not he has an improvement. The prevalence of the process is much less important than in acute lymphoblastic leukemia.

The frequency of improvement in acute myeloblastic and myelomonoblastic acute leukemia is 60-80% under the conditions of modern treatment. Improvement duration reaches

1-2 years, while the life expectancy of patients may exceed 3 years. Up to 10% of patients of all ages recover.