Case Report of Malignancy-Hemophagocytic Lymphohistiocytosis: A Dangerous and Rare Sepsis Mimic

BACKGROUND: Malignancy-hemophagocytic lymphohistiocytosis (M-HLH) is a life-threatening disorder characterized by an aberrant hyperinflammatory immune response triggered by a neoplasm, inherited immune disorders that predispose patients to the development of M-HLH, chemotherapy, infections, and immunotherapy. Due to its aggressive presentation, patients with M-HLH are reported to have a high mortality rate. CASE REPORT: We describe a 66-year-old woman with a history of stage IV breast cancer that presented with multiple admissions for unresolved septic-like presentations. Due to the high clinical suspicion and HLH-2004 criteria, HLH was placed on the differential and further testing revealed a new-onset lymphoma. Treatment was eventually initiated to suppress the hyperinflammatory state of M-HLH and to target the new-onset stage IVB pleomorphic mantle cell lymphoma. Even though treatment was delayed, the patient survived for multiple months longer than the median survival rate. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Emergency physicians should be aware of M-HLH due the hyperaggressive nature of this disease and its elusive presentation; often mimicking common emergency department presentations such as sepsis. The role of the emergency physician should be to stabilize the patient, assess red flags, identify HLH on the differential, and consult with the hematology/oncology service for further testing and potential early treatment.