A 50-year-old Iraqi man presented with splenomegaly and pyrexia of unknown origin. A bone marrow aspirate was done as part of the investigations and unexpectedly showed Plasmodium falciparum parasites. Malaria had not been suspected as this condition is now rare in Iraq but it subsequently transpired that the patient had recently visited Pakistan.
The gametocytes that are observed in the bone marrow differ from those that are observed in the blood, being less mature . The immature gametocytes that are seen include some that are sail-shaped, spindle-shaped or oval (top) rather than the crescent-shaped macrogametocyte and sausage-shaped microgametocyte that are usually observed in the blood. This reflects the fact that gametocytes develop in the internal organs, including the bone marrow, rather than in the circulating blood. Photographs of the bone marrow of this patient show sail-shaped (left), spindle-shaped (centre) and oval (right) immature gametocytes. Some mature gametocytes were also present.