Hemophagocytic Syndrome in a Young Adult Patient with Acute Monoblastic Leukemia: Is It Really Secondary?

Introduction Hemophagocytic lymphohistiocytosis (HLH) has been rarely reported in various subtypes of acute myeloid leukemias (AML), but never in acute monoblastic leukemia. In this report, we present an 18-year-old female with this rare association. Case Presentation Throughout life, the patient suffered from candidiasis and retrobulbar neuritis at the age of 13. Due to sudden onset of fever, sore throat, blurred vision in the right eye, and leukocytes and platelets numbering 115 × 109/L and 66 × 109/L, respectively, the patient was admitted. Visible hemophagocytosis was seen in CD56+/-, CD15+/-, CD68+/- monoblasts in cytology and biopsy specimens. Within 3 days, CT scan detected hepatosplenomegaly, with ferritin, triglycerides, bilirubin, and liver enzyme levels rising, while fibrinogen gradually declined. Thus, the patient displayed 6 features sufficient for HLH diagnosis according to Revised HLH-2004 criteria. Serum IL-2 testing could not be performed. Dexamethasone and Etoposide treatment was immediately initiated in accordance with the HLH-94 protocol. After one week, treatment was switched to the Doxorubicin/Cytarabine “3+7” protocol. Improvement in lab tests was immediate, followed by antileukemic treatment initiation and its normalization achieved by day 20 since starting the antileukemic treatment. Multi-resistant Enterococcus faecalis, Staphylococcus epidermidis, and systemic Candida infections were successfully treated during the aplastic phase. Reassessment during the next hospital stay showed a complete hematological response that led to consolidation with a high dose of cytosine arabinoside. A few days before the planned third hospitalization, she was admitted with 317 × 109/L leukocytes, confusion, incontinence, headache, and vomiting. Leukemic infiltrates and imminent trans-herniation were detected in an endocranial CT scan. Lethal outcome occurred by the end of the second day from admission. Subsequent cytogenetic result showed 46XX, -22, +der 22.- and was interpreted as Emanuel syndrome, an underlying immunodeficiency state. Key Messages for Clinical Practice In conclusion, cytopenia is not reliable criterion for H-score calculation and HLH diagnosis in AML. Etoposide should not be abandoned for treatment of HLH secondary to AML.