(leukemia, malignant) A progressive, proliferative disease of blood cells, originating from myeloid or lymphoid stem cells.

A cancer of the blood and bone marrow characterized by an abnormal proliferation of leukocytes.

A cancer of the blood or bone marrow that is characterized by increased production of abnormal blood cells.

A malignant (clonal) hematologic disorder, involving hematopoietic stem cells and characterized by the presence of primitive or atypical myeloid or lymphoid cells in the bone marrow and the blood. Leukemias are classified as acute or chronic based on the degree of cellular differentiation and the predominant cell type present. Leukemia is usually associated with anemia, fever, hemorrhagic episodes, and splenomegaly. Common leukemias include acute myeloid leukemia, chronic myelogenous leukemia, acute lymphoblastic or precursor lymphoblastic leukemia, and chronic lymphocytic leukemia. Treatment is vital to patient survival; untreated, the natural course of acute leukemias is normally measured in weeks or months, while that of chronic leukemias is more often measured in months or years.

A progressive, malignant disease of the blood-forming organs, characterized by distorted proliferation and development of leukocytes and their precursors in the blood and bone marrow. Leukemias were originally termed acute or chronic based on life expectancy but now are classified according to cellular maturity. Acute leukemias consist of predominately immature cells; chronic leukemias are composed of more mature cells. (From The Merck Manual, 2006)

Cancer that starts in blood-forming tissue such as the bone marrow and causes large numbers of blood cells to be produced and enter the bloodstream.

Leukemia is a term for cancers of the blood cells. Leukemia starts in blood-forming tissues such as the bone marrow. Your bone marrow makes the cells which will develop into white blood cells, red blood cells, and platelets. Each type of cell has a different job: White blood cells help your body fight infection; Red blood cells deliver oxygen from your lungs to your tissues and organs; Platelets help form clots to stop bleeding. When you have leukemia, your bone marrow makes large numbers of abnormal cells. This problem most often happens with white blood cells. These abnormal cells build up in your bone marrow and blood. They crowd out the healthy blood cells and make it hard for your cells and blood to do their work. There are different types of leukemia. Which type of leukemia you have depends on the type of blood cell that becomes cancer and whether it grows quickly or slowly. The type of blood cell could be: Lymphocytes, a type of white blood cell; Myeloid cells, immature cells that become white blood cells, red blood cells, or platelets. The different types can grow quickly or slowly: Acute leukemia is fast growing. It usually gets worse quickly if it's not treated.; Chronic leukemia is slow growing. It usually gets worse over a longer period of time. The main types of leukemia are: Acute lymphocytic leukemia (ALL), which is the most common type of cancer in children. It can also affect adults.; Acute myeloid leukemia (AML), which is more common in older adults but can also affect children; Chronic lymphocytic leukemia (CLL), which is one of the most common types of leukemia in adults. It often occurs during or after middle age.; Chronic myeloid leukemia (CML), which usually occurs in adults during or after middle age. Leukemia happens when there are changes in the genetic material (DNA) in bone marrow cells. The cause of these genetic changes is unknown. For the specific types, there are different factors which can raise your risk of getting that type. Overall, your risk of leukemia goes up as you age. It is most common over age 60. Some of the symptoms of leukemia may include: Feeling tired; Fever or night sweats; Easy bruising or bleeding; Weight loss or loss of appetite; Petechiae, which are tiny red dots under the skin. They are caused by bleeding. Other leukemia symptoms can be different from type to type. Chromic leukemia may not cause symptoms at first. Your health care provider may use many tools to diagnose leukemia: A physical exam; A medical history; Blood tests, such as a complete blood count (CBC); Bone marrow tests. There are two main types - bone marrow aspiration and bone marrow biopsy. Both tests involve removing a sample of bone marrow and bone. The samples are sent to a lab for testing.; Genetic tests to look for gene and chromosome changes. Once the provider makes a diagnosis, there may be additional tests to see whether the cancer has spread. These include imaging tests and a lumbar puncture, which is a procedure to collect and test cerebrospinal fluid (CSF). The treatments for leukemia depend on which type you have, how severe the leukemia is, your age, your overall health, and other factors. Some possible treatments might include: Chemotherapy; Radiation therapy; Chemotherapy with stem cell transplant; Targeted therapy, which uses drugs...

Progressive, malignant disease of the blood-forming organs, characterized by distorted proliferation and development of leukocytes and their precursors in the blood and bone marrow; classified according to degree of cell differentiation as acute or chronic, and according to predominant type of cell involved as myelogenous or lymphocytic.

Leukemia is a malignant condition involving the excess production of immature or abnormal leukocytes, which eventually suppresses the production of normal blood cells and results in symptoms related to cytopenias.

Leukemias are a group of heterogeneous neoplastic disorders of white blood cells. Based on their origin, myeloid or lymphoid, they can be divided into two types.

Leukemia is cancer of the body's blood-forming tissues, including the bone marrow and the lymphatic system.

Leukemia, a cancer of the blood-forming tissues characterized by a large increase in the numbers of white blood cells (leukocytes) in the circulation or bone marrow. A number of different leukemias are classified according to the course of the disease and the predominant type of white blood cell...