What is Chronic Monocytic Leukemia?
Chronic monocytic leukemia is a disease characterized by monoclonal proliferation of the cellular elements of monocytopoiesis.
Pathogenesis during Chronic Monocytic Leukemia
Chronic monocytic leukemia refers to a tumor process with a significant increase in the number of monocytic cells in the blood and bone marrow with normal or low leukocytosis.
In some patients with chronic monocytic leukemia, suppression of erythrocyte and platelet sprouts is not observed for a long time, anemia may occur, which may remain the only symptom of the disease for several years.
Since the increase in the number of monocytes and monocytoid cells in peripheral blood is reactive, for example, with tuberculosis, Waldenstrom macroglobulinemia, and cancer, more or less prolonged monitoring of the blood picture, the exclusion of other somatic diseases as the causes of reactive monocytosis, is sometimes required to diagnose chronic monocytic leukemia.
Elderly people, usually older than 50 years old, get sick with chronic monocytic leukemia, a chronic form of the disease is chronic monocytic leukemia, which develops in children of the first year of life.
Symptoms of Chronic Monocytic Leukemia
The clinical picture of the disease for a long time has no characteristic features. Asymptomatic distinguishes chronic monocytic leukemia from reactive monocytosis, which usually means an exacerbation of the process by which it is caused (tuberculosis, cancer).
Anemia is usually normal or hyperchromic. An enlarged spleen was observed in approximately half of the patients; a significant increase in the liver and lymph nodes is not observed.
The hematological picture of the disease is as modest as the clinical one. Bone marrow hematopoiesis with this leukemia is almost not disturbed for a long time. The ratio of leukocytes and erythrocytes is close to normal, although the study revealed multicellular growth of the bone marrow, and large mononuclear cells do not form large clusters.
In typical cases, the structure of monocytes is not noticeable, therefore, for years, monocytosis in such patients is not considered a sign of a tumor process. In some cases, monocytes have some peculiarity: round, with a slight indentation of the nuclei of a gross structure, an almost colorless cytoplasm with scanty, sometimes dusty, granularity. Sometimes monocytes have fancifully rugged outlines. Young forms – promonocytes and monoblasts – can be found mainly in the terminal stage of the disease.
In the blood of patients with chronic monocytic leukemia, single red nucleated cells are often found.
Most patients have a significant acceleration of ESR; in some cases, this may be one of the earliest laboratory signs of the disease.
With monocytic leukemia (acute and chronic), a lot of lysozyme is contained in the serum and urine of patients, sometimes ten times more than normal. If 4-7 μg / ml of lysozyme are found in normal serum, then with monocytic leukemia – 40-150 μg / ml, in urine – 24-420 μg / ml or more. On this basis, it is possible to distinguish monocytic leukemia from other leukemia and from leukemoid monocytic reactions, in which the content of lysozyme in serum and urine, if elevated, is not so dramatic.
Diagnosis of Chronic Monocytic Leukemia
Diagnosis of chronic monocytic leukemia is based on blood monocytosis, bone marrow monocytosis, bone marrow polymorphic hyperplasia in trepanate with diffuse, non-proliferating, proliferation of monocytic cells, and the detection of a high level of lysozyme in the patient’s serum and urine.
A variant of chronic monocytic leukemia is chronic myelomonocytic leukemia, in which not only monocytosis is observed in the blood and bone marrow, but also an increased content of myelocytes (if a Ph’chromosome is found in a karyological study of chromosomes, then this is a variant of chronic myelogenous leukemia). Morphologically, individual cells are difficult to attribute to monocytes or myelocytes with certainty. In such cases, the myelogram can often be detected only exceeding the normal percentage of myelocytes – 30% or more. Cytochemically in some of these myelocytes in chronic myelomonocytic leukemia, signs of both granulocytic and monocytic growth can be detected. The level of lysozyme in serum and urine is increased, and with this variant of monocytic leukemia. The clinical picture of chronic myelomonocytic leukemia differs little from the picture of monocytic leukemia, however, an enlarged spleen is often observed, sometimes significant.
As the pathological process develops, signs of suppression of normal blood-forming germs become more pronounced, and even before the terminal stage, moderate thrombocytopenia and anemia are detected. The process sometimes ends in a terminal stage, as in chronic myelosis.
The life expectancy of patients with chronic monocytic leukemia exceeds 5-10 years.
Treatment of Chronic Monocytic Leukemia
Chronic monocytic leukemia in a benign stage for a long time does not require any special treatment. Patients with anemia need repeated transfusions of red blood cells. With an increase in thrombocytopenia and the appearance of hemorrhagic syndrome, it is advisable to prescribe small doses of glucocorticosteroids. In the terminal (malignant) stage of the process, the entire complex of cytostatic therapy used to treat acute leukemia is indicated.
Along with the form of chronic monocytic leukemia, which is characteristic of people older than 50-60 years, there is chronic monocytic leukemia in children. As in adult patients with chronic monocytic leukemia, in children the main manifestation remains constant monocytosis in the blood. This feature can be mistaken for hereditary neutropenia, for which monocytosis is also characteristic. The assumption of hereditary neutropenia is supported by the fact that both diseases are detected already in the neonatal period.
In fact, the blood picture in chronic monocytic leukemia differs from that in hereditary neutropenia: in chronic monocytic leukemia, there are always neutrophils in the blood, even a slight left shift in the formula is possible, although there is more or less pronounced neutropenia. In chronic monocytic leukemia in children, often leukocytosis in the blood, an increase in the liver and spleen. These signs are not characteristic of hereditary neutropenia.
In the expanded stage, chronic monocytic leukemia in children does not require the use of cytostatic drugs. If the process is characterized by severe anemia, neutropenia, or a significant increase in lymph nodes, then patients should be kept on glucocorticosteroid therapy for a long time, prescribing the drug in courses of 15 mg / m2 per day for a month with a subsequent break of 3-4 months. If necessary, glucocorticosteroid treatment is advisable to use the method of pulse therapy: the drug is taken 3 days in a row or 3 times every other day for one week, the daily dose is 30-40 mg / m2; the intervals between such courses depend on the effect and can be many months. Red blood cell transfusions for children are needed with a decrease in hemoglobin to 55 g / l and below.
The first detected changes often erroneously lead the doctor to think of infectious mononucleosis, especially if they are combined with fever, catarrhal phenomena in the nasopharynx, tonsillitis, which are not uncommon with this form of leukemia in a child, especially with severe neutropenia.
This situation is allowed by observation and repeated blood tests, re-revealing monocytosis, ultimately the diagnosis of leukemia is clarified using a bone marrow examination. In the bone marrow in chronic monocytic leukemia of a child, as in an adult, there is polymorphic myeloid hyperplasia, although foci of accumulation of monocytes can be more distinct than in an adult. The content of monocytic cells in the bone marrow is increased (reaching tens of percent), and along with monocytes there are promonocytes and even blast cells. A bone marrow examination confirms the diagnosis of leukemia. This chronic leukemia, like others, ends in a terminal stage: blastosis appears in the blood and bone marrow, the liver and spleen increase, and often the body temperature rises, not caused by infection.
In some cases, chronic monocytic leukemia of the child along with monocytosis in the blood is accompanied by a significant increase and densification of the submandibular lymph nodes, containing mainly mature monocytic elements.
The duration of the disease in a child with chronic monocytic leukemia can exceed 10 years.