Familial hemophagocytic lymphohistiocytosis (FHLH)

Abstract

Clinical course and histopathologic features of a typical case of familial hemophagocytic lymphohistiocytosis (FHLH) are presented. FHLH, initially known as familial hemophagocytic reticulosis (FHR), is rare and without proper treatment is invariably rapidly fatal, usually accompanied by fever, anorexia, vomiting, irritability and pallor. Sporadic examples with prolonged survival have been reported. Other significant findings include hepatosplenomegaly, progressive anemia, leukopenia, thrombocytopenia, hyperlipidemia and hypofibrinogenemia. Varying degrees of hemophagocytosis by widely disseminated histiocytes in different organs and structures is one hallmark of the disease. Hemophagocytosis may also occur in viral and bacterial infections and in certain malignant processes. Very high parental consanguinity in FHLH was mentioned in two relatively recent reports. A probable immunologic defect has been the focus of recent investigations. The genetic defect is believed to be transmitted as an autosomal recessive trait.