Hemophagocytic Lymphohistiocytosis Triggered by Leishmaniasis: A Case Report and Literature Review.

BACKGROUND Hemophagocytic lymphohistiocytosis (HLH) is a rare syndrome. It is a result of uncontrolled hyperactivation of the reticuloendothelial system with a release of a huge amount of proinflammatory cytokines in the bloodstream, causing a cytokine storm. It may be primary due to genetic defects and secondary, triggered by viruses, bacteria, parasites, lymphoproliferative, and autoimmune diseases. We present a rare case of HLH triggered by leishmaniasis. HLH accounts for only about 1% of all leishmaniasis cases. CASE REPORT The patient was a 40-year-old previously healthy woman, who has been diagnosed with secondary HLH caused by leishmaniasis. A chronic Epstein-Barr virus (EBV) infection was initially mistakenly interpreted as a trigger agent, because Leishmania amastigotes, present on the first bone marrow biopsy, were not recognized. The treatment with cyclosporin A and corticosteroids suppressed the cytokine storm and prevented the development of complications. Two months later, because of a reactivation of the disease, the patient was referred to a hematologist. A second bone marrow aspiration was performed, in which numerous Leishmania parasites were finally identified. CONCLUSIONS The aim of this case report is to provide more information about the rare phenomenon of secondary HLH triggered by leishmaniasis. Early recognition of the syndrome and its triggering agents will improve disease outcomes and prevent unnecessary treatment with immunosuppressive drugs.