Pappenheimer bodies may be seen in the cytoplasm of mature and immature erythrocytes on a Wright-stained peripheral blood smear. They appear as small dark purple granular bodies of varying size, frequently clustered in groups of two, three, or more near the edge of the cell. They are composed of degenerating cellular remnants that contain iron. Pappenheimer bodies are most likely caused by accelerated red cell division or impaired hemoglobin synthesis.
