Myelodysplastic syndrome (MDS) is a group of disorders that cause abnormal maturation of your blood cells in the bone marrow, leading to low levels of one or more of the blood cells.
There are many subtypes of MDS. Some cases can be stable over many years, while others carry a high risk of becoming acute myeloid leukemia (AML).
The symptoms from MDS are due to the low blood counts and manifest as follows:
MDS is first suspected when there is a low blood count on a blood test. If your doctor suspects that you have MDS, they will recommend for you to undergo a bone marrow biopsy to confirm the diagnosis. From the bone marrow sample, we will look at the appearance of the early cells under the microscope to see if they appear abnormal. This is called dysplasia. They will then decide the number of types of blood cells that have dysplasia, percentage of cancer cells (or blasts) and presence or absence of chromosome abnormalities or gene mutations, to estimate the likelihood of the condition transforming to AML.
Based on the blood counts and findings from the bone marrow biopsy, patients can be categorized into lower and higher risk MDS. These categories are useful to help predict risk of progression to acute leukemia and estimating survival.