Haemophagocytic lymphohistiocytosis occurred during induction chemotherapy in an acute monocytic leukemia patient with FLT3-ITD and DNMT3A mutations

Background: Haemophagocytic lymphohistiocytosis (HLH) is considered to be a large challenge for clinicians due to the variable overlaps of symptoms with other severe diseases and a high rate of mortality. Prompt diagnosis and treatment are crucial to avoid a fatal outcome. However, very limited reports have focused on HLH during chemotherapy (Ch-HLH) due to a low incidence and insufficient knowledge. Case presentation: A 22-year-old male was diagnosed with acute monocytic leukemia with FLT3-ITD and DNMT3A mutations and pulmonary infection. He received IA regimen (Idarubicin, 8 mg/m2/d for 3 days and cytarabine, 100 mg/m2/d for 7 days) chemotherapy, anti-infection drugs and blood components transfusions. During the stage of bone marrow suppression, he presented with a fever, cytopenia (WBC, 0.43×10⁹/L; Hb, 73 g/L and PLT, 1×10⁹/L), refractory coagulation dysfunction (APTT, 104.0 s; PT, 30.5 s and Fbg, 0.87 g/L), splenomegaly (3 cm below the costal margin), hyperferritinemia (SF>3000 μg/L), increased soluble interleukin-II receptors (sIL-2R>7500 u/mL) and haemophagocytosis in the bone marrow and was diagnosed with HLH. After he was treated with methylprednisolone at 500 mg/d for 3 days, 120 mg/d for 3 days and 80 mg/d for 3 days, followed by a gradually reduced dose combined with powerful anti-infection drugs, his symptoms subsided and his abnormal parameters recovered to normal levels. Conclusion: Patients with HLH in acute leukemia have a high rate of mortality. This case report provides helpful clinical experiences relative to the recognition and treatment of Ch-HLH for clinicians.