Hemophagocytic Lymphohistiocytosis: A Primer for Radiologists

OBJECTIVE. The purpose of this article is to provide for radiologists an overview of the radiologic, clinical, and pathologic features of hemophagocytic lymphohistiocytosis. CONCLUSION. Hemophagocytic lymphohistiocytosis is a rare, life-threatening syndrome characterized by abnormal, excessive activation of the immune system. Imaging plays an important role in determining the extent of involvement of hemophagocytic lymphohistiocytosis. Knowledge of this entity, including its imaging, clinical, and pathologic findings, is critical to facilitate timely diagnosis.