Clinically leukemia can be divided into primary leukemia and secondary leukemia. The category of diseases that do not meet the criteria for leukemia at the time of diagnosis but transform into leukemia during the evolution of the disease is what we call secondary leukemia.
Which blood disorders transform into leukemia?
- First is myelodysplastic syndromes, MDS. This is one of the more common types of blood disorders that can turn into leukemia. At one time, MDS was referred to as “smoldering leukemia” and “pre-leukemia”, so the probability of leukemic transformation cannot be ignored. Some patients with MDS, whose disease is not well controlled, may progress to acute myeloid leukemia in a few months or years.
- Secondarily, myeloproliferative neoplasms (MPN). These include primary thrombocythemia, true erythrocytosis, and primary myelofibrosis, which also progress to acute myeloid leukemia in a proportion of patients.
- In addition there is the familiar lymphoma. When tumor cells involve the bone marrow beyond a certain percentage, it also progresses to leukemia.
- There are others that are not so common, such as paroxysmal nocturnal hemoglobinuria, PNH, multiple myeloma, and chronic lymphocytic leukemia.
Of course, once these blood disorders develop into leukemia, there is a difference compared to the primary leukemia. They are more difficult to treat and have a worse prognosis.