Ring sideroblasts are immature red blood cells that have extra iron inside the body of the cell. This extra iron creates a tight ring around the nucleus of the cell.
The body uses iron to make normal, healthy red blood cells. When it is not being used, iron is stored in the bone marrow inside specialized cells called macrophages. A small amount of this iron is also held inside immature red blood cells. The iron inside these cells can be seen under the microscope as small dots within the body of the cell. Pathologists call these dots granules and only a couple of dots are normally seen in healthy cells.
Ring sideroblasts can be seen in a variety of medical conditions. These conditions include copper deficiency, myelodysplastic syndromes, and inherited diseases associated with ring sideroblasts. Some medications and toxins can also be associated with ring sideroblasts.