The Unfolding Mystery of Hemophagocytic Lymphohistiocytosis in Pregnancy: A Case Report.

Hemophagocytic lymphohistiocytosis (HLH) is a rare, life-threatening hyperinflammatory syndrome characterized by uncontrolled immune activation and excessive cytokine release. Pregnancy-associated HLH is particularly uncommon and presents a significant diagnostic challenge because its clinical manifestations frequently overlap with obstetric conditions such as sepsis, hemolysis, elevated liver enzymes, and low platelet count (HELLP) syndrome, and acute fatty liver of pregnancy. We report the case of an 18-year-old primigravid woman at 34 weeks of gestation who presented with persistent fever, fatigue, and progressive clinical deterioration despite antibiotic therapy. Following cesarean delivery, she developed hepatosplenomegaly, jaundice, pancytopenia, hypertriglyceridemia, coagulopathy, and persistent systemic inflammation. Bone marrow aspiration demonstrated hemophagocytosis, fulfilling diagnostic criteria for secondary HLH. The patient required intensive supportive care, including blood product transfusions, before initiating etoposide-based therapy according to the HLH-94/HLH-2004 protocol, with subsequent clinical stabilization and outpatient hematology follow-up. This case highlights the importance of maintaining a high index of suspicion for HLH in pregnant or postpartum patients presenting with persistent fever, cytopenias, liver dysfunction, and hyperinflammatory laboratory findings. Early recognition, prompt multidisciplinary evaluation, and timely initiation of immunosuppressive therapy are essential to reduce morbidity and mortality in this rare but potentially fatal condition.