MDS with ring sideroblasts (RS)

Bone marrow showing normocellular or hypercellular marrow with erythroid hyperplasia, frequently mild to moderate dysplasia; Iron staining showing markedly increased iron stores with ring sideroblasts (RS); erythroid precursors with abnormal perinuclear mitochondrial iron accumulation. Ring siderblasts are defined as erythroblasts in which there are a minimum of five siderotic granules covering at least one third of the circumference of the nucleus.

 
Diagnostic tabel for differentiating MDS.