Abdominal ultrasound findings in children with hemophagocytic lymphohistiocytosis

Hemophagocytic lymphohistiocytosis, a variant of histiocytosis, is characte rized by an uncontrolled activation of the cellular immune system, includin g hepatic mononuclear phagocytic cells. Abdominal ultrasound findings in ch ildren are evaluated in this disease. We present six pediatric cases, two w ith familial and four with sporadic hemophagocytic lymphohistiocytosis, exa mined by abdominal sonography. Three signs were frequently observed: thicke ning 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 imag ing findings are not specific and may be seen in viral hepatitis. However, once hepatitis is excluded, they may suggest the diagnosis of hemophagocyti c lymphohistiocytosis in a critically ill child. A bone smear must be done to establish the diagnosis.