Chronic myelogenous leukemia is a form of cancer that affects white blood cells. It is characterized by the uncontrolled growth of myeloid cells in the bone marrow. It is one of the most common forms of leukemia, accounting for somewhere between 15-20% of all leukemias in adults. It has a strong genetic component, and it is more common in males, the elderly, and people exposed to radiation. Once almost always fatal, it can usually be successfully treated with chemotherapy agents that inhibit tyrosine kinase.
Chronic myelogenous leukemia is difficult to diagnose as it is often asymptomatic, even in the later stages. It is usually discovered during a routine complete blood count. However, it is among the differential diagnosis for any patient presenting with an enlarged spleen or liver. The enlarged spleen can also cause loss of appetite, pain and weight loss. Less commonly, it is diagnosed when it causes bleeding during an infection. It is usually confirmed with a bone marrow biopsy and a test for particular genetic markers.
Most patients who die of the condition go through what is known as a "blast crisis" which often starts with an increase of myeloblasts and basophils, an extremely low or high platelet count and a spleen that continues to enlarge. This can progress to a further increase of myeloblasts and lymphoblasts clustered in the bone marrow and myeloid sarcoma.