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

## TL;DR

A rare case of hyperreactive malarial splenomegaly syndrome in a Swiss patient highlights the importance of considering this condition in travelers returning from malaria-endemic regions.

## Contribution

This case report adds to the limited literature on HMSS in non-tropical settings and emphasizes its diagnostic challenges.

## Key findings

- HMSS can present with nonspecific symptoms and delayed onset after malaria exposure.
- Computed tomography and blood smear confirmed HMSS diagnosis in a patient with a history of malaria-endemic travel.
- The case underscores the need for clinicians to consider HMSS in differential diagnoses of splenomegaly in returning travelers.

## Abstract

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.

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.

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.