An unexpected cause of acute liver failure

A 66-year-old man presented with decompensated acute liver failure with no clear etiology. Eventually, a bone marrow biopsy revealed hemophagocytic cells, and he was diagnosed with hemophagocytic lymphohistiocytosis. This is an uncommon condition in adults, with high morbidity and mortality, and it is often indistinguishable from other forms of acute liver failure. Early clinical suspicion is critical to making the diagnosis, based on meeting at least four of nine specified criteria.