Background: Hemophagocytic lymphohystiocytosis (HLH) is characterized by fever, splenomegaly, pancytopenia, and elevated levels of triglycerides and ferritin. These signs and symptoms are common to other metabolic diseases.
Observation: A 5-month-old female infant, who presented with fever, respiratory distress, massive hepatomegaly, and bicytopenia, was diagnosed as having HLH and chemotherapy was initiated. The patient was negative for familial HLH gene mutations. Respiratory distress and laboratory findings improved rapidly after starting chemotherapy. However, there was no improvement in the massive hepatomegaly and she experienced hypoglycemic episodes. In addition, her family history included a cousin with glycogen storage disease (GSD). On the basis of the findings, the patient was diagnosed as having type Ia GSD. There are no previous reports of HLH secondary to GSD type Ia in the literature.
Conclusions: Congenital metabolic diseases should be considered in the differential diagnosis of children with HLH.