Hemophagocytic Lymphohistiocytosis in Malignant Hematology: Uncommon but Should Not Be Forgotten?

Hemophagocytic lymphohistiocytosis (HLH) is a rare life-threatening syndrome of excessive immune activation and an inflammatory cytokine storm leading to multiple organ failure. We report our experience in a large tertiary referral center on HLH in the setting of hematologic malignancies and describe responses to therapy and outcomes. Seventeen cases of HLH were included in which the most common underlying diagnosis was aggressive lymphoma (n = 7). The median time from diagnosis of primary hematologic condition to HLH was 3.1 months. The most common presenting features were fever (n = 15), splenomegaly (n = 13), and transaminitis (n = 14). The mean serum ferritin level was 21,000 ng/mL. Fourteen patients demonstrated evidence of hemophagocytosis in bone marrow or other organs. Among all patients, 12 received etoposide, 14 received dexamethasone, and 3 received cyclosporine. Intrathecal chemotherapy was administered to 3 patients. Overall, 7 patients (41%) responded to treatment with clinical and laboratory improvement. The median overall survival (OS) from the time of HLH diagnosis and the primary hematologic diagnosis was 8.4 months and 29.5 months, respectively. The OS was better among patients with HLH with aggressive lymphomas (12 months). Response to treatment was associated with better OS. Recognition of manifestations and prompt diagnosis of HLH are crucial to initiate prompt therapy and improve outcome.