Primary myelofibrosis

Introduction to primary myelofibrosis Primary myelofibrosis (PMF) is a chronic myeloproliferative disorder caused by unexplained hematopoietic stem cell abnormalities. The obvious proliferation of myelofibrosis and extramedullary hematopoiesis are the pathological basis of PMF. basic knowledge The proportion of the disease: the incidence of the elderly is more common, about 0.05% - 0.1% Susceptible people: no special people Mode of infection: non-infectious Complications: anemia, ascites, hepatic encephalopathy

Primary myelofibrosis

(1) Causes of the disease

In animal experiments, MF can be induced by certain chemicals, drugs and viruses. Injection of anti-bone marrow serum can also successfully establish an animal model of MF. However, the cause of human PMF is unknown. Some patients with PMF have been exposed to toluene, benzene or ionization. Radiation, the population of Japan's atomic bomb explosion radiation area, the incidence of PMF is 18 times that of people who have not been exposed to radiation.

(two) pathogenesis

Primary myelofibrosis is a clonal blood disease originating from a single pluripotent stem cell. Hematopoietic cells of patients with primary myelofibrosis express the same type of 6-phosphate glucose dehydrogenase (G-6PD) isoenzyme, ie One of the G-6PD A or B types, analyzed by X-linked restriction fragment length polymorphism (RFLP), and subsequently found that the methylation of the calcitonin gene on chromosome 11 confirmed that the peripheral blood cells of the patient were clonal cells; PMF progression The N-ras oncogene 12 codon mutation and p53 tumor suppressor inactivation were found in the blood cells of patients. In vitro stem cell culture system, the number of megakaryocyte progenitor cells (CFU-MK) in peripheral blood and bone marrow of patients increased significantly. The number of other hematopoietic progenitor cells, including CFU-GM, CFU-E, BFU-E and CFU-GEMM, increased to varying degrees, and even the peripheral blood hematopoietic progenitor cells were reported to increase 10 to 20 times more than normal. The experimental results, combined with clinical PMF and other myeloproliferative diseases, can be transformed into acute myeloid leukemia, and can also be transformed into acute lymphoblastic leukemia, all supporting IMF for clonal hematopoietic stem cell disease.

Bone marrow fiber tissue is not a tumorous hyperplasia. In the in vitro culture system of fibroblasts, the patient's CFU-F (fibroblast progenitor cells) is no different from normal people; the patient's non-hematopoietic cells, including fibroblasts, express G-6PD. The two isozymes, and the chromosomal abnormalities of clonal hematopoietic cells, suggest that abnormal proliferation of bone marrow fibroblasts is a secondary response to clonal proliferation of hematopoietic cells, in addition to allogeneic bone marrow transplantation, long-term chemotherapy or After treatment with alpha interferon, MF can disappear, and this view is also supported.

Primary bone marrow megakaryocytes are often proliferating, synthesized in megakaryocytes, and various growth factors stored in alpha particles, such as platelet-derived growth factor (PDGF), epidermal growth factor (EGF), and endothelial cell growth factor (ECGF). ) Basic fibroblast growth factor (bFGF), -transformed growth factor (-TGF) and calmodulin can promote fibrous tissue proliferation. PDGF is important and has mitogenic activity, which promotes fibroblasts into the cell cycle. And stimulate its proliferation and secretion of collagen. Recent studies have shown that -TGF is a major regulator of PMF collagen deposition, which can also be synthesized in endothelial cells and macrophages, and platelet factor 4 (PF4) released by megakaryocytes is inhibited. Collagenase activity reduces the degradation of formed collagen. It can be seen that the excessive proliferation of megakaryocytes and the release of various cytokines are important in the pathogenesis of PMF. In the bone marrow pathological sections of early PMF, there are almost no exceptions for megakaryocytes. The cells proliferated significantly, and support was also provided from morphology. It was also reported that tumor necrosis factor (TNF, TNF) and interleukin released by bone marrow cells. -1 (IL-1) also stimulates fibroblast proliferation. These various cytokines can also be released from other clonal hematopoietic cells, and their levels are elevated in peripheral blood and bone marrow.

Immune abnormalities mediate fibrous tissue hyperplasia. Some autoantibodies can be detected in the serum of some PMF patients, such as antinuclear antibodies, rheumatoid factor, anti-cardiolipid fat body; Coombs test positive reaction; circulating immune complex, complement activity And immunoglobulin increased; plasma cell-like lymphocytes in the bone marrow; glucocorticoid treatment has a certain effect, a small number of systemic lupus erythematosus, nodular polyarteritis, scleroderma and amyloidosis combined with MF report Some people think that immune complexes can bind to platelets through FC receptors, prompting them to release cytokines such as PDGF, leading to fibrous tissue proliferation. Therefore, considering some PMF as another immune abnormal disease unrelated to clonal hematopoietic stem cell disease, it is called My own immune myelofibrosis.

The pathogenesis of extramedullary hematopoiesis, early literature emphasizes that due to the proliferation of bone marrow fibrous tissue, the hematopoietic cells are gradually reduced. As compensation, organs in the hematopoietic function of the fetus, such as the spleen, liver, lymph nodes, etc., are responsible for part of the hematopoiesis. Extramedullary hematopoiesis, also known as myeloid metaplasia, has been confirmed to have hematopoietic function in the liver pathology. The number of CFU-GM in splenic venous blood is significantly higher than that in splenic arterial blood and peripheral blood, which is evidence of hematopoietic function of spleen. The compensatory hematopoietic theory cannot explain the normal hematopoietic cells in the early stage of PMF. Even when hyperproliferation occurs, the spleen has developed myeloid metaplasia. Therefore, the authors suggest that extramedullary hematopoiesis is caused by abnormal hematopoietic cells escaping from the bone marrow and being hosted in other organs. It has also been confirmed that the patient's bone marrow sinusoidal type IV collagen deposition and fibrosis, the integrity of the sinus wall is destroyed, so that abnormal hematopoietic cells can enter the circulation. In addition, extramedullary hematopoiesis do not account for systemic hematopoiesis even in the late stage of PMF. Main position.

Primary myelofibrosis prevention

1. Avoid contact with radiation and chemicals such as benzene and lead. Protective measures should be strictly implemented for occupational needs that are often exposed to these damaging factors.

2, strengthen nutrition, more protein and a variety of vitamins. Can be more appropriate to kidney, nourishing food, such as walnuts. Red dates, peanuts, etc. Applicable to anemia, weakness and other symptoms of bone marrow suppression after chemotherapy.

3, daily life, food and drink should be regular, work and rest, diet should be moderate, especially pay attention to not eating too much frying, smoked, over-focus, rubber food.

Primary myelofibrosis complications Complications, anemia, ascites, hepatic encephalopathy

The most common complications are infection, fever, anemia, anemia, heart failure, portal hypertension, ascites, liver failure, hepatic encephalopathy, and spleen infarction.

Symptoms of primary myelofibrosis Common symptoms Abdominal pain, weight loss, fatigue, paraplegia, urinary lymphadenopathy, increased intracranial pressure, coma, ascites dysfunction

PMF insidious onset, slow progress, often have a long period of asymptomatic period before diagnosis, and some years, even more than 10 years, this period can account for about 2 / 3 of the entire course of disease, the only clinical manifestations It is a splenomegaly. Some people estimate that the enlarged spleen represents about 1 year of disease per 1cm (under the ribs). About 20% of patients have no symptoms at the time of diagnosis. They are often found in routine examinations or other diseases. PMF is found. There are clinical manifestations of the following groups of pathophysiological changes.

Extramedullary hematopoiesis

Most of them involve the spleen, which is often swollen. In 40% of cases, this is the first performance. The splenomegaly of 1/3 to 1/2 patients does not exceed the umbilical level, and the other 2/3 to 1/2 patients have splenomegaly. And extending to the pelvic cavity, often to the right beyond the midline, the spleen texture is hard, can clearly clear the sputum and the incision, the spleen can cause the left upper abdomen to pull the feeling, when the stomach is pressed, there is a feeling of fullness and loss of food, and the spleen infarction or spleen Peripheral inflammation is rare, showing severe left upper abdominal pain, even left shoulder pain, tenderness in the spleen area, can touch the friction and smell and friction, and can be associated with left responsive pleurisy. A few patients have no spleen at the time of diagnosis, but B The spleen has enlarged during ultrasound or CT examination.

Liver enlargement accounts for 50% to 80%, mostly mild to moderate enlargement, only 20% of patients with liver enlargement > 6cm under the rib, but some patients after splenectomy can progressively increase liver, beyond the umbilical plane, or even enter In the pelvic cavity, swollen lymph nodes are rare, and 10% to 20% of cases are mildly enlarged.

Extramedullary hematopoiesis sometimes has a more specific clinical manifestation:

(1) Fibrohemopoietic extramedullary tumors: The tumor is composed of hematopoietic tissue and may be associated with obvious fibrosis. It is found in the skin, mucous membrane, respiratory tract, gastrointestinal tract, adrenal gland, kidney, mediastinum and thymus, breast and prostate. A small number can occur in the central nervous system, including the intracranial or spinal epidural space, producing severe signs of nervous system, such as headache, vomiting, optic disc edema and other manifestations of increased intracranial pressure, can also occur convulsions, coma and other consciousness Obstacles, in addition, there are limb sensations and abnormal activities, and even hemiplegia, paraplegia, tumors can be diagnosed by various imaging examinations, such as CT, MRI, myelography and positron emission tomography (PET), qualitative judgment, Hematopoietic cells can also be implanted into the serosa, mainly megakaryocytes, or immature granulocytes, occasionally immature red blood cells, which cause chest, abdomen or pericardial effusion, respectively. Most of the effusion occurs after splenectomy, exudate The above-mentioned naive hematopoietic cells can be found, and extramedullary hematopoietic tumors may be the result of increased hematopoietic progenitor cells in the circulation. Loss of function also predisposing factors.

(2) portal hypertension and ascites: seen in 6% to 8% of advanced cases, the spleen caused a significant increase in portal blood flow, local vascular volume expansion and blood stasis, and even thrombosis; intrahepatic hematopoietic cell infiltration and fibrosis The vascular compliance of the liver is reduced, and the above pathological changes lead to portal hypertension, manifested as ascites, esophageal and gastric varices bleeding, and portal thrombosis, and a few cases may also be complicated by hepatic encephalopathy.

Hypermetabolic syndrome

Mainly seen in the early and middle stages of the disease, when the bone marrow hematopoietic cells proliferate excessively, the metabolism is hyperthyroidism, and the patient has symptoms such as fatigue, night sweats, weight loss, and even hypothermia, but only a small number of patients have the above-mentioned performance.

3. Bone marrow failure

Mostly seen in the late stage of PMF, due to bone marrow hematopoietic disorders, anemia is the most common, bone marrow erythroid depression and ineffective hematopoiesis, red blood cell life shortened, red blood cells stay in the enlarged spleen, plasma volume expansion and associated bleeding or hemolysis are anemia The reason for this is that a group of reports have 54% of patients with paroxysmal nocturnal hemoglobinuria-like defects.

Other performance

The abnormally cloned megakaryocytes produce poor platelet quality, the number of advanced megakaryocytes decreases, and the retention of spleen causes thrombocytopenia, causing hemorrhage, inhibition of myeloid granules and hypersplenism to reduce white blood cells, especially neutrophils. , easy to concurrent infection, other clinical manifestations are still:

(1) bone pain: foreign cases are common, domestic cases are rare, pain may be associated with trabecular bone hyperplasia, associated with osteosclerosis or periostitis, more common lower extremity pain, rare cases due to concurrent granulocytic sarcoma (Granulocytic sarcoma ), causing bone damage, can also produce bone pain.

(2) Dermatitis: painful maculopapular rash, the pathology is neutrophil infiltration, similar to Sweet syndrome, skin lesions can progress to bullae or pyoderma and gangrene, skin lesions are rare in domestic cases, pathologically It is different from leukemia and has nothing to do with infection and vasculitis.

(3) Gout: The incidence of foreign cases is 6%, which may be accompanied by renal colic. It is caused by uric acid crystal deposition in the urinary tract. In a few cases, gout is the first manifestation of PMF.

Examination of primary myelofibrosis

Peripheral blood

(1) Chronic medullary fibrosis: 1/2 to 1/3 of patients have mild or moderate positive cytochrome anemia at the initial visit, and early patients have a slight increase in the number of mild red blood cells, and patients with severe medullary fibrosis Severe persistent anemia can occur. Mature red blood cells in blood samples often show different sizes and deformities. Sometimes they see teardrops, ovals, target or polytropic red blood cells, teardrop-shaped red blood cells in peripheral blood, and red blood cells. The myelocytes and giant platelets are one of the characteristics of the peripheral blood laboratory of this disease. In the peripheral blood samples of 36 cases of 50 cases in Shanghai, 1 to 21 nucleated cells were observed at the same time for every 100 white blood cells. In cases where the spleen has been resected, nucleated red blood cells are more markedly increased, and reticulocytes are slightly increased to 3% to 5%.

The total number of white blood cells varies, and the diagnosis is mostly at (4-10)×109/L. In about half of the cases, the white blood cells can be increased to (10-20)×109/L, although the total number of individual white blood cells is as high as 100×109/L. However, it is rarely more than (60 ~ 70) × 109 / L, in some cases 15% ~ 25% of patients at the time of diagnosis, the total number of white blood cells is normal, a small number of white blood cells decreased, about 70% of cases of peripheral blood found in young and late Cells, even 1% to 5% of myeloblasts, we have seen 2 cases of chronic medullary fibrosis, and the peripheral blood granulocytes are as high as 12% to 24% for many years. Therefore, the granulocytes of the blood of this disease are increased, not necessarily This indicates that the disease has been transformed into acute leukemia, but if the protozoa in the short-term peripheral blood and bone marrow increase rapidly, it should be wary that the chronic myelin has been converted to acute leukemia, and the blood eosinophils or basophils in some patients are increased. In a few cases, the Pelger-Hut nuclear abnormality appeared in white blood cells.

Platelet counts vary. The number of platelets in early cases can be increased, up to 1000×109/L, but it decreases with the development of the disease. Platelets are large and deformed. Occasionally, megakaryocyte fragments may be seen, and the function of platelets may be defective.

(2) Acute medullary fibrosis: Peripheral blood of acute medullary fibrosis accounts for a decrease in whole blood cells or a decrease in the number of white blood cells with significant anemia or thrombocytopenia, and the number of reticulocytes is low, and teardrop-like red blood cells are generally not seen. There may be no red blood cells, but there may be more primitive cells. Promyelocytes or young red blood cells resemble acute leukemia. The bone marrow is mostly hyperplasia or dry pumping. There are reports of bone marrow biopsy or ultrastructure showing the increase of protomegaloblasts. .

(3) Children's medullary fiber: Children's patients have more peripheral blood leukocytes, and the number of platelets is mostly low.

2. Histochemical staining

In about 2/3 chronic cases, the granulocyte alkaline phosphatase score is abnormally increased, a few are normal, and the individual is reduced, so sometimes this point can be distinguished from the slow granule phase, while the scores of acute cases are mostly normal, such as chronic medullary fibers have been combined or When transformed into leukemia, the granulocytes can be expressed by histochemical staining of the corresponding type of leukemia. For example, the primordial cells in the patient's bone marrow are positive for platelet peroxide staining, and the monoclonal antibodies against platelet glycoprotein IIb/IIIa or Ib are positive. This indicates the possibility of conversion to megakaryoblastic leukemia.

3. Bone marrow smear examination

The phenomenon of dry pumping when pumping bone marrow fluid is one of the typical manifestations of this disease. The so-called dry pumping refers to the phenomenon that bone marrow is hard to be obtained due to the hard bone of the patient. Hematopoietic cells, especially megakaryocytes, still see hyperplasia, but as medullary fibrosis worsens, the megakaryocytes of the bone marrow can sometimes proliferate. Other hematopoietic cells tend to proliferate. When converted to acute leukemia, the blast cells of the bone marrow Significantly increased.

4. Bone marrow biopsy

It has an important pathological change of bone marrow, which is an indispensable basis for the diagnosis of this disease. It seems that bone marrow reticular fibers and collagen fibers are increased in all cases, and bone hyperplasia can be seen in severe cases, but it should be noted that only scattered in the early stage of the lesion may be seen. Fusiform fibroblasts have not seen obvious collagen fibrous tissue, and sometimes fusiform cells are difficult to find. For example, hematoxylin-eosin or Giemsa staining alone, reticular fibers are not easy to develop color, but silver is added. Staining can show a significant increase in reticular fibers. In the early stage of medullary fibrosis, the number of nucleated cells, granulocytes and megakaryocytes are proliferated, and erythroid cells are normal or reduced. In addition to the abnormalities seen in megakaryocytes, the nucleus may be nucleated. There are too many or too few lobes, acquired Pelget-Hut abnormalities, and nucleoplasm development is not synchronized.

5. Chromosome examination

Except for individual reports that typical medullary fibers have appeared in Philadelphia chromosomes, most authors believe that there are no Philadelphia chromosomes or other characteristic chromosomal abnormalities that are positive for diagnosis, and only a few cases have trisomy chromosomal abnormalities. Reilly 1994 Twenty-nine of the 63 patients with chronic primary medullary fibers (including 3 with immunosuppressive agents) reported chromosomal abnormalities, the most common being the 13th, the deletion of the long arm of chromosome 20 [del(13 q), Del(20q)] and part III trisomy abnormalities; karyotype abnormalities increased significantly when the disease was converted to acute leukemia, and it was suggested that chromosomal abnormalities such as at the time of diagnosis may indicate that the prognosis is not good.

6. Biochemical examination

Serum uric acid, blood and urine lysozyme content may increase, serum vitamin B12, vitamin B12 binding protein value can also be seen increased, basal metabolic rate increased, erythrocyte sedimentation rate can be slightly increased.

7. X-ray examination

X-ray examination of 30% to 70% of cases has signs of osteosclerosis; typical X-ray findings are an increase in the density of bone density, accompanied by a spotted translucent area, forming a so-called "glass-like" phenomenon. It can be seen that the trabecular bone is thick or fuzzy, the medullary cavity is narrow, the edge is irregular, the periosteum is irregularly thickened, etc., B-ultrasound examination, hepatosplenomegaly.

8 radionuclide bone marrow scan

With 99mTc-sulfur colloid, 99mTc-sodium phytate can show the mononuclear macrophages of bone marrow, normal human trunk bone, long bone, spleen and liver can be developed. Extramedullary hematopoiesis can be seen in patients with medullary fibers. A large amount of 99mTc accumulates in the part.

9.B Ultra

Show liver splenomegaly.

10. Progenitor cell culture

The culture of semi-solid medium in vitro showed that the number of CFU-G, CFU-MM and CFU-GEMMeg in peripheral blood of some patients with myelin may increase.

Diagnosis and diagnosis of primary myelofibrosis

diagnosis

1. Domestic diagnostic criteria

(1) The spleen is large.

(2) Anemia, immature grains and red blood cells appear in peripheral blood.

(3) Multiple failures of bone marrow puncture or "dry pumping", or smear showing "hypoplasia".

(4) Pathological examination of liver, spleen and lymph nodes showed hematopoietic foci.

(5) Bone marrow biopsy showed significant proliferation of reticular fibers and/or collagen fibers.

Item (5) above is a prerequisite, plus any two of the other four items, and can exclude secondary myelofibrosis, can be diagnosed as IMF.

2. The American Polycythemia (PV) Collaborative Group developed the IMF diagnostic criteria in 1983.

(1) The spleen is large.

(2) Peripheral blood smears have immature granules and red blood cells.

(3) The number of red blood cells is normal, and the Ph chromosome is negative.

(4) In the pathological section of bone marrow biopsy with good material, fibrous tissue accounted for more than 1/3.

(5) Excluding other systemic diseases.

Foreign diagnostic criteria emphasize the need to exclude PV, so the number of red blood cells is required to be normal, but in fact some PMF patients may have a slight increase in the number of red blood cells in the early stage, and may be associated with anemia in the late stage. Domestic standards suggest that extramedullary hematopoiesis are more meaningful, but It is often difficult to perform in actual clinical work. Therefore, it is still emphasized that bone marrow biopsy pathology shows that fibrosis is the most important diagnostic basis. All other items are reference conditions, and PMF can be finally diagnosed after exclusion of secondary.

Differential diagnosis

1. Secondary myelofibrosis (SMF)

(1) Myeloproliferative diseases (MPD): Chronic myeloid leukemia (CML), PV, essential thrombocythemia (ET) and PMF are all in the MPD category. The first three MPDs can be treated in the course of the disease, especially in the advanced stage. Merging MF, it should be carefully identified.

1CML: Both PMF and CML can have splenomegaly, peripheral blood appears immature granules, red blood cells, and many cases of advanced CML are accompanied by myelofibrosis. The difference between the two is: CML has a longer leukemia course before SMF Ph chromosome positive, Bcr-abl fusion gene positive, normal or reduced neutrophil ALP score and normal red blood cell morphology, no teardrop red blood cells.

2PV: Some PMF patients have increased red blood cells and even red blood cell capacity, while in advanced PV, 15% to 20% of cases are accompanied by SMF, so the two are sometimes confused. The identification point is: PV has a long time before SMF occurs. The course of erythrocytosis and elevated red blood cell volume, there are many signs of blood quality, usually no deformity and teardrop-like red blood cells, peripheral blood immature granules, red blood cells are rare, in addition, combined with SMF PV, its disease development is much faster than PMF, After an average of 3 years of death, 25% to 50% progress to acute leukemia.

3ET: Some PMF patients have a marked increase in platelets during the course of disease, and ET is often accompanied by SMF. The difference between the two is that ET has a long course of platelet elevation before the occurrence of SMF, which may be accompanied by thromboembolism or Hemorrhagic complications, usually without deformed red blood cells and teardrop-shaped red blood cells, immature grains, red blood cell blood is rare, ET develops into SMF, far less than CML and PV.

(2) myeloid anemia: bone marrow metastasis (the most common adenocarcinoma), diffuse atypical mycobacterial infection can be associated with anemia, immature granules, red blood cell blood, bone marrow can also be associated with fibrosis, so sometimes need and PMF identification, primary disease diagnosis and discovery of tumor cells and mycobacteria in the bone marrow as the identification points, and other reports, tumor with SMF, urinary hydroxyproline emission increased, while PMF or tumor patients without SMF are normal .

2. Myelodysplastic syndrome (MDS) and acute leukemia (AL) with myelofibrosis: Almost all hematopoietic stem cell diseases can be associated with myelofibrosis, but most of them are reticular fibers, few collagen fibers proliferate, many The authors believe that fibrosis is a reactive response. In the diagnosis of MDS or AL, with SMF, up to 30% to 72%, but only 10% in severe cases. Only MDS with severe myelofibrosis is discussed below. And AL.

(1) MDS with SMF: patients with typical MDS characteristics, including no organ enlargement, complete blood cell reduction and its corresponding clinical signs, peripheral blood and bone marrow showed 2 or 3 lines of morbid hematopoiesis, blast cells <30%, Bone marrow biopsy:

1 shows fibrosis, mainly reticular fibers.

2 have heterogeneous megakaryocytes.

3 primordial cells, diverse forms, not in pieces or clusters, not enough to diagnose leukemia, histochemical staining and immunophenotyping are difficult to determine, MDS with bone marrow fibrosis often progress rapidly, clinical process is dangerous, easy to develop into acute Myeloid leukemia (AML), with poor chemotherapy effect, mostly died within 1 year. Some people think that this is a special type of acute myelofibrosis. Some authors have suggested that this is the acceleration period in the process of PMF conversion to AML.

According to the typical MDS clinical and hematological features of MDS with SMF, most of the spleen is not swollen or only slightly enlarged. The bone marrow fibrosis is light and mainly composed of reticular fibers. In most cases, it is not difficult to distinguish from IMF.

(2) Acute myelofibrosis (AMF): AMF patients often have a "dry pumping" of bone marrow puncture, or smear shows a decrease in proliferation, with a small amount of primordial cells or without primordial cells; peripheral blood often shows complete blood cell reduction, no tears Droplet-shaped red blood cells, but with a small amount of primordial cells; bone marrow biopsy showed primitive cell infiltration with difficult to determine type, with obvious fibrosis, this primitive cell was observed under electron microscope, platelet myeloperoxidase staining positive; bone marrow immunophenotype or group Staining examination, platelet glycoprotein GPIIB/IIIA, (CD41) and GPIb (CD61) positive; patients with rapid clinical progress, poor chemotherapy, often died in a short period of time, the literature has been named malignant myelofibrosis and AMF, due to the above Histochemical staining and immunophenotypic or histochemical staining have confirmed the source of megakaryocytes in this original cell line. Therefore, it has been officially named as acute megakaryocytic leukemia. The FAB classification belongs to M7 type of AML, accounting for about 5% of AML. Lymph nodes, hepatomegaly, and splenomegaly are rare. According to the clinical onset of M7, the infiltration of organs and the above morphological and immunophenotypic or histochemical staining, it is not difficult and PMF. do not.

3. Other diseases with spleen

(1) Spotted syndrome: PMF with splenomegaly as the main manifestation, especially with peripheral blood cell reduction and/or portal hypertension, easy to be confused with spotted syndrome, carefully examine blood smears, find immature granules, red blood cells In order to identify the main points, difficult cases need to be differentiated by bone marrow biopsy.

(2) Chronic lymphoid leukemia: including chronic lymphocytic leukemia (CLL), chronic lymphocytic leukemia (CPLL) and hairy cell leukemia (HCL), all with spleen, especially HCL often accompanied by bone marrow puncture "dry pumping" Confused with PMF, careful examination of blood smear is the key to identification, CLL, CPLL are mainly lymphocytes, the latter can also appear naive lymphocytes; HCL can be found in hair cells, difficult to use phase contrast microscope and electron microscope Identification, while PMF is characterized by immature granules and red blood cells. Further bone marrow aspiration and biopsy can be clearly distinguished.

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