What is Subleukemic Myelosis?
Subleukemic myelosis refers to leukemia, manifested by somewhat increased polymorphic cell myeloproliferation such as panmyelosis or myelomegakaryocytic myelosis, progressive myelofibrosis and osteomyelosclerosis, splenomegaly, hepatomegaly with three-growth myeloid metaplasia in these and others.
Causes of Subleukemic Myelosis
The literature did not meet data on the structure of the incidence of subleukemic myelosis.
Pathogenesis during Subleukemic Myelosis
Some researchers believe that with subleukemic myelosis, the process of hematopoiesis is initially disturbed at the level of the myelopoiesis progenitor cell. Its belonging to hemoblastoses and the secondary nature of myelofibrosis are based on studies of G-6-PD types in blood cells and fibroblasts of bone marrow and skin in mulattos heterozygous for this enzyme. According to one concept, myelofibrosis in this form of leukemia is caused by megakaryocytes and platelets that produce a germ factor that enhances fibroblast proliferation. The topography of myelofibrosis corresponds to areas of accumulation of megakaryocytes. Proponents of the affiliation of subleukemic myelosis with leukemia indicate myeloid metaplasia in the spleen and other organs, the final exacerbation of the process as a blast crisis, the presence of a malignant form of the disease and the sensitivity of such patients to cytostatic therapy.
Symptoms of Subleukemic Myelosis
With a benign version of subleukemic myelosis, a detailed clinical picture is preceded by a long asymptomatic period. Life expectancy from the moment of diagnosis ranges from 1.5 to 5 years, there are cases of a longer course of the disease (15-20 years or more).
Malignant forms of subleukemic myelosis are characterized by acute (subacute) or fulminant course, early onset of blast crisis, deep thrombocytopenia, and severe hemorrhagic syndrome leading to death. Infectious complications, heart and liver failure, and thrombosis often join. In 10-17% of cases, portal hypertension with varicose veins of the esophagus is diagnosed.
The approximate formulation of the diagnosis:
- Subleukemic myelosis; a favorable course with a slow increase in the size of the spleen and liver, anemia, white blood cells, platelets and the development of myelofibrosis.
- Subleukemic myelosis; acute course with a marked increase in the spleen and liver, early development of blast crisis, anemia, deep thrombocytopenia with hemorrhagic syndrome (brain, nasal and gingival bleeding), myelofibrosis.
Subleukemic myelosis is more often found in people over 40 years old. Sometimes for many years, patients do not notice any signs of the disease, go to the doctor with complaints of weight loss, recurring fever, pain in the bones and in the spleen. Against the background of hemostasis failure and thrombocytopenia, hemorrhages occur in the skin, joints, and frequent bleeding from the veins of the esophagus and stomach. Anemia is more often normochromic, rarely megaloblastic or hemolytic in nature. In some cases, erythrocytosis and an increase in erythropoiesis in the bone marrow are detected. In the hemogram, the number of leukocytes is increased, sometimes reduced, neutrophilia with a shift to the left is noted. The platelet count is increased or normal, they are functionally inferior. In the myelogram – megakaryocytosis (immature forms). In the bone marrow – narrowing of the cavities filled with fibrous tissue. In the enlarged spleen, liver and other organs and tissues, foci of extramedullary hematopoiesis of a polymorphic composition.
Diagnosis of Subleukemic Myelosis
The diagnosis of subleukemic myelosis is established on the basis of clinical data and the results of a study of the state of hematopoiesis (hemogram, myelogram, bone marrow biopsy).
Subleukemic myelosis is differentiated from chronic myelogenous leukemia occurring with subleukemic leukocytosis. The detection of the Ph’-chromosome is a strong argument in favor of myelogenous leukemia.
Differential diagnosis should also be carried out between subleukemic myelosis and secondary myelofibrosis, which can develop with malignant neoplasms, prolonged infections (tuberculosis), as well as with toxic effects (benzene and its derivatives, etc.).
Treatment of Subleukemic Myelosis
In the early stages of subleukemic myelosis with moderate anemia and splenomegaly, which does not cause abdominal discomfort, cytostatic treatment should not be used; can be limited to restorative therapy. Indications for the appointment of cytostatics are splenomegaly with compression syndrome and the phenomena of hypersplenism, thrombocythemia with the threat of thrombosis, progressive blastemia, pletor.
Myelobromol is prescribed at 250 mg / day with an initial number of leukocytes of at least 15-20 * 109 / l and a normal platelet count, a course dose of 4-10 g. With a slightly lower number of them, glucocorticoid and anabolic hormones are prescribed previously, for 7-14 days. . The drug is canceled when white blood cells reach 6-7 * 109 / l, and platelets – 100-150 * 109 / l.
Cyclophosphamide, whose antitumor effect is less pronounced than myelobromol, is prescribed – in cases of a reduced number of leukocytes and platelets – 200-400 mg / day intravenously at intervals of 1-3 days (course dose of 10-12 g) in combination with glucocorticoid hormones. In blast crisis, the principles of treatment of acute leukemia are used.
Radiation therapy on the area of the sharply enlarged spleen causes a short-term positive effect, stopping the phenomena of abdominal discomfort, however, the development of deep cytopenia is possible.
Splenectomy is indicated mainly in cases of deep hemolytic crises that are not amenable to drug therapy, with the threat of rupture of the spleen and its recurring heart attacks, with severe hemorrhagic thrombocytopenic syndrome. Splenectomy is contraindicated in the terminal stage, with thrombocytosis and hypercoagulation.
Glucocorticoid hormones are prescribed for hemolytic anemia, cytopenia, prolonged fever of non-infectious origin, arthralgia. Anabolic hormones (nerobol, retabolil) are indicated for anemia due to erythropoiesis insufficiency, long-term treatment with glucocorticoid hormones. With deep anemia, transfusions of red blood cells are used; thrombocytopenic hemorrhagic syndrome serves as an indication for transfusions of thromboconcentrate. With iron deficiency anemia, iron preparations are prescribed.