Answer to Case 205

Answer:  No parasites present.  A nucleated red blood cell, reticulocytes, and Howell-Jolly and Pappenheimer bodies are shown.  These findings are consistent with the patient's known asplenia and are no cause for concern.  Because the Pappenheimer bodies can be confused with intra-erythrocytic parasites, it is sometimes useful to perform an iron stain on a peripheral blood film.  Pappenheimer bodies will stain strongly positive (bright blue) while the parasites will not.

Pappenheimer bodies on iron stain, 1000 times original magnification

Note the rim of blue staining iron particles around the nucleus of the nucleated RBC (upper right corner of below image)

Howell-Jolly bodies may also be mistaken for intra-erythrocytic parasites but can be differentiated by their large round dark blue-purple shape with lack of accompanying cytoplasm.  See this Previous Case of the Week for an example of Howell-Jolly bodies.