Hemophagocytic lymphohistiocytosis masquerading as progressive chronic lymphocytic leukemia.

Hemophagocytic lymphohistiocytosis (HLH) is a potentially fatal syndrome characterized by a non-malignant expansion of the macrophage population in the setting of a heightened cytokine response with subsequent widespread hemophagocytosis. It can occur as either genetic or acquired forms; the latter of which frequently occurs in the setting of infection, autoimmune disease, or malignancy. We present the second known case of HLH associated Chronic Lymphocytic Leukemia (CLL) in the absence of infectious etiology and review the current literature.