Hyperreactive malarial splenomegaly syndrome: a rare cause of splenomegaly in Switzerland (case report).

Background: Hyperreactive malarial splenomegaly syndrome (HMSS) is a rare cause of splenomegaly in a nontropical setting. Symptoms of HMSS are nonspecific, rendering the diagnosis challenging. If left untreated, the condition is potentially fatal. Case Summary: We herein detail the case of a young male presenting to the emergency department with fever and abdominal pain. Travel history included multiple trips to malaria endemic regions, the last trip dating back to 3 years before the consultation. Splenomegaly was identified via computed tomography (CT) scan, and a blood smear revealed Plasmodium falciparum infection (parasitemia of <0.1%). After excluding other causes of splenomegaly, HMSS was diagnosed and treated accordingly. Conclusion: A remarkable aspect of this case is the length of time elapsed between the last visit to an endemic region and symptom onset. This case report highlights the need to include HMSS in the differential diagnosis for splenomegaly in a traveler returning from an endemic region.