Hemophagocytic Lymphohistiocytosis Syndrome As Presenting Sign For Acute Monocytic Leukaemia- A Case Report.

Background: Hemophagocytic lymphohistiocytosis (HLH) is a rare aggressive syndrome of excessive immune activation. Clinical manifestations of this syndrome mimic various other clinical conditions making the diagnosis harder to achieve. These manifestations are believed to be a result of cytokine storm which leads, eventually, to a multi-organ failure and eventually death. The latter two might be prevented if HLH was diagnosed early. HLH is classified into primary consist of monogenic disorders and secondary occurs as a complication in various settings such as infection, autoimmune disease, and malignancy. In hematologic malignancies, HLH is classically associated with specific entities, mainly, lymphoma or induced by treatment-related infections. Acute myeloid leukemia, on the other hand, is less common trigger with only few case reports.   Case presentation: An 83-years-old, 5 years free of transitional cell man, presented with unstable atrial fibrillation was intubated and shortly after that he developed a multi-organ failure. Bicytopenia and a high level of ferritin aroused a clinical suspicion of HLH syndrome. Further evaluation revealed high levels of soluble interleukin 2 receptors and no activity of natural killers cells. A bone marrow was performed and it did not show phagocytosis, however, acute myeloid leukemia (AML) was diagnosed. AML was suggested to be associated with chemotherapy that our patient received 5 years earlier.   Conclusion: Hemophagocytic lymphohistiocytosis can be present as a multi-organ failure requiring a high index of suspicion. Chemotherapy related-AML can be a trigger for HLH.