Cytoplasmic inclusion Information and Courses from MediaLab, Inc.

Auer rods are red staining, needle-like bodies seen in the cytoplasm of myeloblasts, and/or progranulocytes in leukemia. Auer rods are cytoplasmic inclusions which result from an abnormal fusion of the primary (azurophilic) granules. Single or multiple Auer rods may be seen in the cytoplasm of a cell. If more than one is present, they are frequently close together and may even be overlapping. Their identification is very important because, if found, they can confirm the presence of myeloblasts indicating the presence of a myeloid (non-lymphoblastic) leukemia. They can also be seen in myeloid blast crisis in chronic granulocytic leukemia. Auer rods are never seen in lymphoblasts. This differentiation is important because the treatment of lymphoblastic and myeloblastic leukemia are different. Auer Rods are always classified as pathological.

In 1952 Chediak (a Cuban physician) reported a childhood disorder in which abnormal cytoplasmic inclusions appeared in the neutrophils of four family members. In 1954 Higashi reported a similar abnormality in an 11-month old Japanese infant. These inclusions were identified as lysosomal in origin and found in this rare autosomal recessive disorder Death was usually related to recurrent infections or hemmorhage though now some of the affected patients live to reproduce. Ocular and cutaneous albinism, increased susceptibility to pyogenic infections, abnormal granules in neutrophils, and a bleeding tendency are prominent findings. The striking neutrophilic inclusions appear as coarse intra-cytoplasmic azurophilic granules (see photograph).These granules arise from dilated portions of the Golgi-endoplasmic reticulum lysosomal apparatus. Aleutian mink and other animals are known to have Chediak-Higashi syndrome. Azurine pelts from infected mink were once prized by coat makers.