Dear Editor,Haemophagocytic lymphohistiocytosis (HLH) may be triggered by various infectious or non-infectious conditions (1). HLH has rarely been associated with visceral leishmaniasis (VL) (2), and as far as we know, never with a sinus histiocytosis with massive lymphadenopathy (Rosai-Dorfman (RD) disease (3)).We report a case of life-threatening HLH associated with VL in a patient suffering from a RD disease and highlight the potential connections between HLH and histiocytosis.On 24 December 2012, a 64-year-old man presented with a 3-week history of high-grade fever, night sweats and weight loss. He was just returning from a 2-month stay in Morocco where he was born, but he had been living in France for 30 years. Clinical examination showed bilateral cervical lymph nodes that were known for several years with recent enlargement and hepatosplenomegaly. Laboratory blood tests showed haemoglobin 8 g/dL, platelets 8 G/L, leukocytes 1.7 G/L, low fibrinogen 0.7 g/L, elevated ferritin, LDH ...