The WHO International Working Group on Morphology of MDS (IWGM-MDS) defined three types of sideroblasts: # Type 1 sideroblasts: fewer than 5 siderotic granules in the cytoplasm # Type 2 sideroblasts: 5 or more siderotic granules, but not in a perinuclear distribution # Type 3 or ring sideroblasts: 5 or more granules in a perinuclear position, surrounding the nucleus or encompassing at least one third of the nuclear circumference. Type 1 and type 2 are found in non-sideroblastic anemias. Type 3 is found only in<unk> .
Sideroblastic anemia
Refractory anemia with ring sideroblasts
Myelophthisic anemia
Myomatous erythrocytosis syndrome
Refractory anemia with excess of blasts
Congenital hypoplastic anemia
Hereditary spherocytosis
Thiamine responsive megaloblastic anemia syndrome