Introduction Leukemia is a malignant neoplasm of hematopoietic tissue originating in and infiltrating the bone marrow . Leukemia generally involves the peripheral blood, and often infiltrates the spleen, liver, and lymph nodes. Normal Marrow Leukemic Marrow Leukemia is classified into the major categories of acute and chronic leukemia.
Acute leukemia is characterized byproliferation of immature cells or blasts .
If untreated, death usually occurs within 6 months in most patients. Acute Leukemia Chronic leukemia is a proliferation of mature appearing cells , again in the marrow, peripheral blood, and various organs. The clinical course is relatively indolent, compared with acute leukemia, and ranges from 2-6 years depending on the subtype of the proliferating cell. While classification of the acute leukemias is fairly straight forward, the classification of chronic bone marrow neoplasms is less clear. A classification scheme based on our current knowledge, is presented on the next page.