Final answer:
Leukemia is a type of cancer that starts in the bone marrow, leading to the production of abnormal white blood cells, and without treatment, it can be fatal within a few months.
Step-by-step explanation:
The condition described is likely to be leukemia, a type of cancer predominantly found in children affecting the blood cells. It originates in the bone marrow and has the potential to disseminate to other parts of the body. Without proper treatment, leukemia can prove fatal within a matter of months.
Leukemia often manifests through the production of an excessive number of abnormal white blood cells, disrupting the normal function of the blood and causing symptoms such as fatigue, infections, and easy bruising. Fortunately, treatments including chemotherapy, radiation, and potentially bone marrow transplants can treat the disease effectively.