Secondary myelofibrosis

Introduction to secondary myelofibrosis Secondary myelofibrosis refers to a group of diseases in which bone marrow hematopoietic tissue fibrosis caused by various causes affects hematopoietic function. basic knowledge Sickness ratio: 0.05% Susceptible people: no specific population Mode of infection: non-infectious Complications: essential thrombocytopenia anemia

Secondary myelofibrosis

(1) Causes of the disease

The literature on secondary myelofibrosis in the literature is still very few, and there is no systematic and continuous report. The mechanism of bone marrow fibrosis caused by some causes is unclear. Some cases have existing hematopoietic stem cells or mesenchymal stem cells. The internal defects, or allergic factors, need further research. Only some of the causes of abnormal proliferation of bone marrow fibrous tissue are listed (Table 1), and are briefly described as follows. The comprehensive causes may be chemical, physical, infectious, and tumor. , autoimmune, hypoparathyroidism, hyperthyroidism, etc.

Chemical solvent (20%):

Long-term exposure to organic solvents such as benzene and carbon tetrachloride. In 1941 Rawson et al reported 5 cases of long-term exposure to benzene and 1 case of long-term exposure to carbon tetrachloride, but the history of exposure was more than several years, the longest 1 For example, in contact with Styda's 26-year-old benzene contact, there is a lack of systematic observation and research on solvent-induced secondary myelofibrosis.

Ionizing radiation (20%):

In 1945, Hiroshima, Japan, had 10 patients with myelofibrosis affected by atomic bombing with myeloid metaplasia. Six of them died of comorbidities and had pathological anatomy, which was confirmed to be typical myelofibrosis; the other 3 cases have been transformed. The bone marrow fibrosis of leukemia; the other case is slow granule combined with myelofibrosis. According to statistics, the incidence of atomic bombing is 4.5 times higher than that of those not affected by atomic bombing.

Infection (20%):

Severely infected cases of myelofibrosis are rarely found, and even if they are covered by the manifestations of infection, there have been reports of disseminated tuberculosis in the bone marrow fibrosis at home and abroad before the 1960s, but some authors believe that tuberculosis is advanced. Complications of primary myelofibrosis, patients with tuberculosis often involve the lungs, chest, heart, liver, pancreas, lymph nodes, bone marrow and other organs; bone marrow, ribs, spine and other parts of the bone marrow can be fibrous connective tissue Alternative; spleen, liver, lymph nodes, etc. may have extramedullary hematopoiesis, tuberculosis caused by secondary medullary fibrosis has a mild age, high fever, splenomegaly, lymph node enlargement and other characteristics, the patient's tuberculosis is serious and broadcast Dispersed, the course of the disease is shorter.

Tumor (10%):

In addition to chronic granules, hematopoietic leukemia, acute leukemia and other hematopoietic malignancies are often associated with secondary myelofibrosis. Bone marrow fibrosis, ulcerative cancer, gastric cancer, lung cancer, breast cancer, etc. can occur in the pre-leukemia stage of myeloproliferative abnormalities. Metastatic bone cancer, the destruction of bone marrow hematopoietic tissue can cause fibrosis and hardening reaction of bone marrow.

Other (5%):

Systemic lupus erythematosus, parathyroid dysfunction or diseases caused by vitamin D metabolic disorders can also produce secondary myelofibrosis.

(two) pathogenesis

The difference between secondary and primary myelofibrosis is that there should be pathological changes in the primary pathogenesis of secondary myelofibrosis, such as the primary site of metastatic bone cancer and bone marrow biopsy and smear of cancer cell infiltrating tissue. Check, should also have the same cancer cells as the primary tumor; bone marrow fibrosis caused by systemic disseminated tuberculosis, pathological manifestations of tuberculosis in the lungs, lymph nodes, spleen, bone, etc., except for myelofibrosis It is also seen that osteoclasts and osteogenesis are consistent with secondary fibrosis. In addition, primary myelofibrosis often shows comprehensive hematopoiesis of three series of hematopoietic cells in extramedullary hematopoietic organs such as the liver. Most of the myelofibrosis is manifested as a series of extramedullary hematopoiesis.

Secondary myelofibrosis prevention

There is no effective preventive measure for this disease. Early detection and early diagnosis are the key to the prevention and treatment of this disease.

Secondary myelofibrosis complications Complications thrombocytopenia anemia

The duration of myelin disease varies from a few months to 30 years. Generally, the natural course of disease is about 5 to 7 years on average, and the average survival time after diagnosis is about 3 to 5 years. The prognosis is related to the following factors: unexplained fever, bleeding tendency, ineffective erythropoiesis, hemolysis, hepatomegaly, plasma iron turnover, and bone marrow cell proliferation. Asymptomatic in general diagnosis, the survival period is longer, the more severe the symptoms, the shorter the survival period. The mortality rate is about 40% in the first year after diagnosis. Most of the causes of death are heart failure, bleeding, acute leukemia and infection. About 20% of patients with advanced acute leukemia. Common complications include various symptoms caused by spleen compression, anemia, and bleeding.

Secondary myelofibrosis symptoms Common symptoms Weak bloating weight loss

The clinical symptoms and signs of secondary myelofibrosis are the comprehensive manifestations of primary disease and myelofibrosis. In addition to the clinical features of myelofibrosis, hematopoietic disorders and extramedullary hematopoiesis, there are also The systemic and local clinical features caused by the onset of the disease, and the symptoms and signs of the primary disease are often significant and early appearance, so often mask the performance of myelofibrosis.

There is no uniform diagnostic criteria for secondary myelofibrosis, but the diagnosis can be referred to the following points:

1 Secondary myelofibrosis should have a clearer underlying cause, history and corresponding clinical manifestations.

2 have symptoms of myelofibrosis, such as: progressive anemia, weight loss, fatigue, splenomegaly caused by left upper abdominal distension.

3 have extramedullary hematopoietic manifestations, such as: spleen, liver, lymph nodes progressive swelling.

4 peripheral blood appeared young red, agranulocytic anemia.

5 bone marrow biopsy confirmed bone marrow fibrosis, pumping may be dry pumping.

6 The age of onset is generally lower than that of primary myelofibrosis.

7 etiology treatment, can cause some of the symptoms caused by the primary disease to disappear.

Secondary myelofibrosis

Peripheral blood

Hemoglobin is reduced, red blood cells are reduced, red blood cells are different in size, reticulocytes are slightly increased, and extramedullary hematopoiesis occurs. There are nucleated red blood cells or myelocytes, but white blood cells and platelet counts may be normal or near normal.

2. Serum alkaline phosphatase

Increased to metastatic bone cancer, bone biopsy to find cancer cells, bone fracture and new bone formation.

3. Bone marrow biopsy

For bone marrow fibrosis, bone wear can be dry pumping, such as benzene or radiation sickness can have the corresponding inhibition of bone marrow hematopoietic cells.

4. X-ray examination

There is a wide range of osteolytic phenomena.

5. According to clinical manifestations, symptoms, signs, B-ultrasound, electrocardiogram and other tests.

Diagnosis and diagnosis of secondary myelofibrosis

Mainly related to the identification of primary myelofibrosis, recently authors believe that the determination of hydroxyproline in the urine of patients, help distinguish tumors with secondary bone marrow fibers and primary myelofibrosis, the former group of patients with urinary hydroxy Proline content is increased, while primary myelofibrosis and urinary hydroxyproline content in patients with myelofibrosis secondary to tumors are within the normal range.

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