+Four major kinds of<unk>  Cell type Acute Chronic Lymphocytic<unk> (or "lymphoblastic") Acute lymphoblastic<unk>  (ALL) Chronic lymphocytic<unk>  (CLL) Myelogenous<unk> ("myeloid" or "nonlymphocytic") Acute myelogenous<unk>  (AML or myeloblastic) Chronic myelogenous<unk>  (CML) An explanation of acute<unk>  General classification Clinically and pathologically,<unk>  is subdivided into a variety of large groups. The first division is between its acute and chronic forms: * Acute<unk>  is characterized by a rapid increase in the number of immature blood cells. The crowding that results from such cells makes the bone marrow unable to produce healthy blood cells resulting in low hemoglobin and low platelets. Immediate treatment is required in acute<unk>  because of the rapid progression and accumulation of the malignant cells, which then spill over into the bloodstream and spread to other organs of the body. Acute forms of<unk>  are the most common forms of<unk>  in children. * Chronic<unk>  is characterized by the excessive buildup of relatively mature, but still abnormal, white blood cells. Typically taking months or years to progress, the cells are produced at a much higher rate than normal, resulting in many abnormal white blood cells. Whereas acute<unk>  must be treated immediately, chronic forms are sometimes monitored for some time before treatment to ensure maximum effectiveness of therapy. Chronic<unk>  mostly occurs in older people but can occur in any age group. Additionally, the diseases are subdivided according to which kind of blood cell is affected. This divides<unk> s into lymphoblastic or lymphocytic<unk> s and myeloid or myelogenous<unk> s: * In lymphoblastic or lymphocytic<unk> s, the cancerous change takes place in a type of marrow cell that normally goes on to form lymphocytes, which are infection-fighting immune system cells. Most lymphocytic<unk> s involve a specific subtype of lymphocyte, the B cell. * In myeloid or myelogenous<unk> s, the cancerous change takes place in a type of marrow cell that normally goes on to form red blood cells, some other types of white cells, and platelets. Combining these two classifications provides a total of four main categories. Within each of these main categories, there are typically several subcategories. Finally, some rarer types are usually considered to be outside of this classification scheme. Specific types * Acute lymphoblastic<unk>  (ALL) is the most common type of<unk>  in young children. It also affects adults, especially those 65 and older. Standard treatments involve chemotherapy and radiotherapy. Subtypes include precursor B acute lymphoblastic<unk> , precursor T acute lymphoblastic<unk> , Burkitt's<unk> , and acute biphenotypic<unk> . While most cases of ALL occur in children, 80% of deaths from ALL occur in adults. * Chronic lymphocytic<unk>  (CLL) most often affects adults over the age of 55. It sometimes occurs in younger adults, but it almost never affects children. Two-thirds of affected people are men. The five-year survival rate is 85%. It is incurable, but there are many effective treatments.<unk>  subtype is B-cell prolymphocytic<unk> , a more aggressive disease. * Acute myelogenous<unk>  (AML) occurs far more commonly in adults than in children, and more commonly in men than women. It is treated with chemotherapy. The five-year survival rate is 20%. Subtypes of AML include acute promyelocytic<unk> , acute myeloblastic<unk> , and acute megakaryoblastic<unk> . * Chronic myelogenous<unk>  (CML) occurs mainly in adults; a very small number of children also develop this disease. It is treated with imatinib (Gleevec in United States, Glivec in Europe) or other drugs. The five-year survival rate is 90%.<unk>  subtype is chronic myelomonocytic<unk> . * Hairy cell<unk>  (HCL) is sometimes considered a subset of chronic lymphocytic<unk> , but does not fit neatly into this category. About 80% of affected people are adult men. No cases in children have been reported. HCL is incurable but easily treatable. Survival is 96% to 100% at ten years. * T-cell prolymphocytic<unk>  (T-PLL) is a very rare and aggressive<unk>  affecting adults; somewhat more men than women are diagnosed with this disease. Despite its overall rarity, it is the most common type of mature T cell<unk> ; nearly all other<unk> s involve B cells. It is difficult to treat, and the median survival is measured in months. * Large granular lymphocytic<unk>  may involve either T-cells or NK cells; like hairy cell<unk> , which involves solely B cells, it is a rare and indolent (not aggressive)<unk> . * Adult T-cell<unk>  is caused by human T-lymphotropic virus (HTLV), a virus similar to HIV. Like HIV, HTLV infects CD4+ T-cells and replicates within them; however, unlike HIV, it does not destroy them. Instead, HTLV "immortalizes" the infected T-cells, giving them the ability to proliferate abnormally. Human T-cell lymphotropic virus types I and II (HTLV-I/II) are endemic in certain areas of the world. * Clonal eosinophilias (also called clonal hypereosinophilias) are a group of blood disorders characterized by the growth of eosinophils in the bone marrow, blood, and/or other tissues. They may be pre-cancerous or cancerous. Clonal eosinophilias involve a "clone" of eosinophils, i.e., a group of genetically identical eosinophils that all grew from the same mutated ancestor cell. These disorders may evolve into chronic eosinophilic<unk>  or may be associated with various forms of myeloid neoplasms, lymphoid neoplasms, myelofibrosis, or the myelodysplastic syndrome. Pre-leukemia * Transient myeloproliferative disease, also termed transient<unk> , involves the abnormal proliferation of a clone of non-cancerous megakaryoblasts. The disease is restricted to individuals with Down syndrome or genetic changes similar to those in Down syndrome, develops in a baby during pregnancy or shortly after birth, and resolves within 3 months or, in ~10% of cases, progresses to acute megakaryoblastic<unk> . Transient myeloid<unk>  is a pre-leukemic condition.
Leukemia
Paracoccidioidomycosis
Pythiosis
Progressive vaccinia
Agranulocytosis
Granulocytosis
Acute leukemia
Leukopenia