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Chronic Myelomonotic Leukemia (CMML) is a rare, chronic neoplastic disease of the haematopoietic system. It belongs to the overlapping syndromes of the myelodysplastic-myeloproliferative syndrome. What are the causes and symptoms of CMML and how is it treated?

Chronic Myelomonotic Leukemia (CMML) occurs mainly in elderly men. It is much more often diagnosed in males than in females (2: 1), and the mean age at diagnosis is 65-75 years of age. According to the literature, there are 0.6-0.7 / 100,000 new cases of CMML every year.

The risk factors for developing chronic myelomonocytic leukemia are not yet known.

A typical feature of her is the proliferation of monocytic cells in the peripheral blood and bone marrow, and dysplasia of one or more cell lines of the hematopoietic system.

For this reason, the World He alth Organization (WHO) includes chronic myelomonocytic leukemia among the so-called overlap syndromes of the myelodysplastic-myeloproliferative syndrome.

A characteristic feature in the clinical picture of the disease is the presence of monocytosis, i.e. an increased number of monocytes in the peripheral blood.

Due to ineffective hematopoiesis associated with bone marrow cell dysplasia and its fibrosis, patients also often suffer from anemia and thrombocytopenia.

Chronic Myelomonocytic Leukemia: Symptoms

Chronic myelomonocytic leukemia may be asymptomatic for a long time.

Patients most often visit their family doctor's office because of weight loss, chronic fatigue, shortness of breath, palpitations, as well as skin changes and bleeding from the nose or gums.

The basic test that makes it possible to suspect a neoplastic disease is the complete blood count, which should be performed in each patient presenting the above symptoms.

It should be remembered, however, that the blood count results are not sufficient to diagnose a neoplastic disease, but only an introduction to further, specialized diagnostics.

Symptomspresented by patients most often result from a reduced number of blood morphotic elements: erythrocytes, neutrophilic granulocytes (neutrocytes) and platelets.

The general symptoms of chronic myelomonocytic leukemia include:

  • unintentional weight loss in a relatively short period of time
  • lack of appetite
  • chronic fatigue, weakness, drowsiness, shortness of breath, easy fatigue, decreased tolerance to exercise, palpitations, pale skin - these are typical symptoms presented by a patient with anemia, i.e. too low level of hemoglobin in the blood. The norm for the male sex is the hemoglobin value in the range of 14-18 g%, and for the female sex 11.5-15.5 g%.
  • infections, frequent colds and infections that are difficult to treat and recur - result from neutropenia, i.e. a reduced number of neutrocytes in the peripheral blood. These are neutrophils, belonging to the leukocytes (white blood cells). These cells play an immune function in our body, prevent inflammation and destroy pathogens through phagocytosis.
  • bleeding from the nose, ears, gums, easy bruising, petechiae on the skin - are a typical symptom of hemorrhagic diathesis, they indicate thrombocytopenia, i.e. a reduced number of blood platelets in the peripheral blood plasma. The normal number of platelets is considered to be 150-440 thousand / mm3 of blood.
  • gingival overgrowth
  • dark night sweats
  • fever and low-grade fever for no apparent reason
  • hepatomegaly, or enlargement of the liver, which is palpable on the abdominal examination in the right hypochondrium projection
  • splenomegaly, i.e. enlargement of the spleen, which is palpable on the abdominal examination in the left hypochondrium projection; may cause pain in the left epigastric region
  • lymphadenopathy, i.e. enlargement of peripheral lymph nodes. The patient can feel painless, hard lumps sliding against the skin, most often located around the neck, armpits and groin

Chronic myelomonocytic leukemia: morphological types

Currently, the literature describes two types of chronic myelomonocytic leukemia, CMML type 1 (i.e. myelodysplastic syndrome type leukemia) and CMML type 2 (i.e. myeloproliferative syndrome type leukemia).

Criteria for recognition of CMML type 1

  • peripheral blood leukocytosis less than 13,000 / mm3 of blood
  • Peripheral blood blast cells percentage is lower than 5%
  • the percentage of blast cells in the bone marrow is lowerthan 10%

Criteria for recognition of CMML type 2

  • peripheral blood leukocytosis over 13,000 / mm3 of blood
  • the percentage of blasts in the peripheral blood is 5-19%
  • the percentage of blast cells in the bone marrow is 10-19% or the presence of Auera (these are sticks visible in the cytoplasm of blast cells after specialized staining of the tissue preparation) with the number of blast cells in the blood or marrow less than 20%
  • spleen enlargement is common

Chronic myelomonocytic leukemia: research and diagnosis

Diagnostic criteria for chronic myelomonocytic leukemia according to the World He alth Organization (WHO):

  • Monocytosis in the peripheral blood. The number of monocytes exceeds 1000 cells / microliter of blood.
  • Missing Philadelphia chromosome (Ph chromosome), which is formed as a result of translocation between chromosomes 9 and 22, t (9,22), and thus the lack of the BCR-Abl1 fusion gene, which is the result of this mutation.
  • The content of blasts (commonly called blasts) in the bone marrow is less than 20%, and in the peripheral blood greater than 5%. These are immature stem cells from which, depending on their type, various hematopoietic cells develop in the bone marrow.
    In order to determine the presence and amount of these cells in the bone marrow and / or peripheral blood, microscopic examination of the collected tissue material should be performed.
    To establish the diagnosis, the doctor orders peripheral blood count with a smear (physiologically blast cells, in he althy people, not found in the peripheral blood), as well as histopathological examination of the bone marrow.
    In order to collect bone marrow for examination, it is necessary to perform a bone marrow aspiration biopsy or percutaneous bone marrow biopsy, i.e. invasive procedures performed in a hospital setting.
    BAC (Fine Needle Aspiration Biopsy) involves collecting the bone marrow using a specialized needle with a syringe. Percutaneous bone marrow biopsy involves taking a bone fragment together with the bone marrow with a thick, sharp needle, after prior skin anesthesia.
    Most often, the bone marrow is collected from one of the iliac bones (they form the pelvis together with the pubic, ischial and sacrum bones), and more specifically from the posterior upper iliac spine and from the sternum.
    The method of choice is fine-needle bone marrow aspiration, but in some cases this method does not provide material for testing due to bone marrow fibrosis (in 30% of patients suffering fromchronic myelomonocytic leukemia). Then a percutaneous bone marrow biopsy should be performed.
  • Dysplasia, i.e. disorders of differentiation, maturation and structure of one or more hematopoietic cell lines, from which, as a result of many transformations, red blood cells, platelets and leukocytes (basophils - basophils, eosinophils, eosinophils, neutrophils - neutrophils) are formed and lymphocytes). This results in anemia, hemorrhagic diathesis, and increased susceptibility to infections and decreased immunity.

Chronic Myelomonocytic Leukemia: Differentiation

As chronic myelomonocytic leukemia does not have typical clinical symptoms and does not have any typical genetic abnormalities, it is necessary to differentiate it from other malignancies of the bone marrow.

Particular attention should be paid to:

  • chronic myeloid leukemia (CML)
  • atypical chronic myeloid leukemia (aCML)
  • acute monocytic leukemia
  • reactive monocytosis.

In order not to make a mistake and make an accurate diagnosis, it is necessary to perform many specialized laboratory and histopathological tests using cytochemical and immunohistochemical staining, as well as flow cytometry.

Pay attention to the differentiation of monocytosis, i.e. an increased amount of monocytes in the peripheral blood, which may result from the presence of bacterial, viral, fungal infections, systemic connective tissue diseases, cirrhosis, or sarcoidosis. Monocytosis is also often seen in people taking glucocorticosteroids, and even in pregnant women.

Chronic Myelomonocytic Leukemia: Treatment

Bone marrow transplantation is the best known and, according to the literature, providing the best results.

Allogenetic Hematopoetic Sten Cell Transplantation (HSCY) involves stem cells collected from a donor. It is considered the most effective method of treating chronic myelomonocytic leukemia.

Another therapeutic method is the use of hypomethylating drugs (e.g. Azacitidine and Decitabine) and cytostatics (e.g. Hydroxyurea, Etoposide).

It is also possible to use symptomatic treatment or the waiting attitude in CMML therapy, if the disease is asymptomatic.

Chronic Myelomonocytic Leukemia:follow-up after treatment

Patients who have undergone pharmacological treatment and bone marrow transplantation should remain under the supervision of the attending hematologist and undergo periodic laboratory tests to diagnose possible relapse or progression of the disease as early as possible.

Chronic myelomonocytic leukemia: prognosis

The prognosis for chronic myelomonocytic leukemia is poor. The average survival time of patients varies between 1.5-3 years from the time of diagnosis. It should be noted that CMML may progress to Acute Myeloid Leukemia (AML).

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Category:

Oncology