Malignancy associated hemophagocytic lymphohistiocytosis in children

Hemophagocytic lymphohistiocytosis (HLH) is a rare disorder of immune dysregulation resulting in abnormal T-cell activation and inflammatory cytokine production which produces a constellation of clinical features unique to HLH. Pediatric secondary HLH is usually triggered by infection, malignancy, or rheumatological disorders. The diagnosis of malignancy-associated HLH (MA-HLH) poses a difficult challenge as clinical features may be attributed to the underlying disease or chemotherapy. Our study aimed to see the occurrence of this rare entity at our centre.

Data were collected from all pediatric oncology patient treated at our center with the diagnosis of MA-HLH from January 2012 to December 2014. Data were collected for age, sex, underlying disease, treatment protocol, stage of chemotherapy, any underlying infection, treatment given for HLH, and outcome.

There were five patients with a diagnosis of MA-HLH in the study period. Age ranged from 18 months to 9 years. Of the five MA-HLH, two patients had acute lymphoblastic leukemia, two acute myeloid leukemia, and one had Hodgkin lymphoma. The three patients who had documented microbiological infection also did not improve after appropriate treatment. Two patients died during treatment. One patient improved completely on steroid alone. One patient received HLH 2004 induction.

The delay in the diagnosis of MA-HLH in pediatric patients may be due to decrease awareness about the condition the timely diagnosis of MA-HLH is crucial for a better outcome. Herein, we discuss our experience with this rare entity in pediatric oncology patients with review of literature.