Diagnosis: Malaria tropica
Description: Swollen stellate cells with black and brown pigmented malaria pigments and phagocitized red blood cells.
Additional finding: birefringent pigment
Clinical presentation: 22 year old male tourist, developed fever while in Kenya. Two days later septic cardiovascular shock and disseminated intravascular coagulation with acute renal failure.
Commentary: Through increased phagocytosis and depletion of erythrocytes splenomegaly develops. The black and brown malaria pigmentation (hemozoin) develops through disassembly of hemoglobin by the parasites. It is visible in erythrocytes as small black spots in stellate cells and portal macrophages of the liver as well as in reticulum cells of the spleen. Liver and spleen are macroscopically stained grey. The renal tubuli contain hemoglobin cylinders. The pigmentation can be shown in liver and bone marrow biopsies and is iron-negativ. In cases of severe Malaria tropicana, throphozoites of Plasmodium falciparum are visible in the erythrocytes.