Cerebellar swelling due to familial hemophagocytic lymphohistiocytosis: An unusual presentation

•Cerebellar swelling leading to obstructive hydrocephalus is a rare presentation of familial HLH.•Familial HLH has no specific marker and the diagnosis relies on clinical grounds.•High degree of clinical suspicion may allow good outcome of this treatable condition.

BackgroundCerebellar swelling with obstructive hydrocephalus is a rare but life threatening condition, associated with different etiologies, familial hemophagocytic lymphohistiocytosis (HLH) being rarely one of them.Patient2-year-7-month old boy presented with irritability, cerebellar dysfunction, and somnolence. Brain MRI showed marked diffuse cerebellar swelling and obstructive hydrocephalus with mild tonsillar herniation. Laboratory testing revealed pancytopenia, elevated liver enzymes, elevated ferritin and triglycerides levels and decreased fibrinogen. The diagnosis of familial HLH was confirmed by the presence of homozygous missense mutation of Syntaxin 11 gene. The child was treated with HLH-2004 protocol of chemotherapy followed by allogenic stem cell transplantation. His neurological condition improved significantly after treating the underlying disease.ConclusionCerebellar swelling is a rare manifestation of familial HLH. High degree of clinical suspicion may allow a timely diagnosis and appropriate therapy.