Abdominal ultrasound findings in children with hemophagocytic lymphohistiocytosis.

Hemophagocytic lymphohistiocytosis, a variant of histiocytosis, is characterized by an uncontrolled activation of the cellular immune system, including hepatic mononuclear phagocytic cells. Abdominal ultrasound findings in children are evaluated in this disease. We present six pediatric cases, two with familial and four with sporadic hemophagocytic lymphohistiocytosis, examined by abdominal sonography. Three signs were frequently observed: thickening of the gallbladder wall (all cases), increased periportal echogenicity (four cases), and enlarged lymph nodes in the porta hepatis (four cases). Hepatomegaly, splenomegaly, and ascitic fluid may also be found. These imaging findings are not specific and may be seen in viral hepatitis. However, once hepatitis is excluded, they may suggest the diagnosis of hemophagocytic lymphohistiocytosis in a critically ill child. A bone smear must be done to establish the diagnosis.