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Anemia in myelophthisis: causes, symptoms, diagnosis, treatment
Last reviewed: 04.07.2025
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Anemia in myelophthisis is normochromic-normocytic and develops with infiltration or replacement of normal bone marrow space by nonhematopoietic or abnormal cells. Anemias are caused by tumors, granulomatous diseases, and lipid storage diseases. Bone marrow fibrosis is common. Splenomegaly may develop. Characteristic changes in peripheral blood are anisocytosis, poikilocytosis, and the presence of erythrocyte and leukocyte precursors. Diagnosis usually requires trephine biopsy. Treatment consists of supportive care and elimination of the underlying disease.
The descriptive terminology used for this type of anemia can be confusing. Myelofibrosis, in which bone marrow is replaced by fibrous tissue, may be idiopathic (primary) or secondary. True myelofibrosis is a stem cell abnormality in which fibrosis is secondary to other hematopoietic events. Myelosclerosis is new bone formation that is sometimes accompanied by myelofibrosis. Myeloid metaplasia reflects the presence of extramedullary hematopoiesis in the liver, spleen, or lymph nodes and may be accompanied by myelophthisis from another cause. The older term idiopathic myeloid metaplasia refers to primary myelofibrosis with or without myeloid metaplasia.
[ Causes anemia in myelophthisis
The most common cause is replacement of bone marrow by metastases of a malignant tumor (usually the mammary gland or prostate, less often the kidneys, lungs, adrenal glands or thyroid gland); extramedullary hematopoiesis is not typical. Other causes include myeloproliferative diseases (especially in the late stages or progressive erythremia), granulomatous diseases and storage diseases (lipids). Myelofibrosis may occur in all of the above cases. In children, a rare cause may be Albers-Schönberg disease.
Myeloid metaplasia may result in splenomegaly, especially in patients with storage diseases. Hepatosplenomegaly is rarely associated with myelofibrosis due to malignant tumors.
Risk factors
Factors contributing to decreased red blood cell production may include a decrease in the number of functioning hematopoietic cells, metabolic disturbances associated with the underlying disease, and, in some cases, erythrophagocytosis. Extramedullary hematopoiesis, or destruction of the bone marrow cavities, causes the release of young cells. Abnormal red blood cell shapes often result from increased red blood cell destruction.
Symptoms anemia in myelophthisis
In severe cases, symptoms of anemia and the underlying disease occur. Massive splenomegaly may cause increased intra-abdominal pressure, early satiety, and left upper quadrant abdominal pain. Hepatomegaly may be present.
Myelophthisis is suspected in patients with normocytic anemia, particularly in the presence of splenomegaly, if there is a potential underlying disorder. If suspected, a peripheral blood smear should be examined, since the presence of immature myeloid cells and nucleated red blood cells such as normoblasts suggests myelophthisis. The anemia is usually of moderate intensity and normocytic, but may tend to be macrocytic. Red blood cell morphology may show extremes in size and shape (anisocytosis and poikilocytosis). The white blood cell count may vary. The platelet count is often low, with giant, bizarrely shaped platelets. Reticulocytosis is common, and may be due to release of reticulocytes from the bone marrow or extramedullary areas and is always indicative of hematopoietic regeneration.
Diagnostics anemia in myelophthisis
Although peripheral blood examination may be informative, bone marrow examination is necessary for diagnosis. Indications for puncture may be leukoerythroblastic changes in the blood and unexplained splenomegaly. Obtaining a bone marrow aspirate is often difficult; trephine biopsy is usually required. The changes found depend on the underlying disease. Erythropoiesis is normal or in some cases increased. However, the life span of red blood cells is often reduced. Foci of hematopoiesis may be found in the spleen or liver.
Radiography of the skeletal system may reveal bone changes (myelosclerosis) characteristic of long-term myelofibrosis or other bone abnormalities (osteoblastic or lytic lesions in bone) that suggest the cause of the anemia.
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Treatment anemia in myelophthisis
Treatment of the underlying disorder. In idiopathic cases, supportive care is given. Erythropoietin (20,000 to 40,000 units subcutaneously once or twice weekly) and glucocorticoids (eg, prednisolone 10 to 30 mg orally daily) may be used, but response is usually modest. Hydroxyurea (500 mg orally daily or every other day) shrinks the spleen and normalizes red blood cell levels in many patients, but response may take 6 to 12 months. Thalidomide (50 to 100 mg orally daily in the evening) may produce a modest response.