# Intramuscular Aseptic Cyst Syndrome: A Case Report and a Review of the Literature

## TL;DR

This paper reports a rare case of aseptic cyst syndrome in the leg muscles and emphasizes the need for careful diagnosis and multidisciplinary treatment.

## Contribution

The paper presents a rare case of intramuscular aseptic cyst syndrome and highlights effective treatment with corticosteroids and immunosuppressants.

## Key findings

- Aseptic cyst syndrome can present in the hamstrings and gastrocnemius muscles with symptoms mimicking infection.
- Surgical debridement and antibiotics were insufficient, but corticosteroids and immunosuppressants led to rapid improvement.
- Multidisciplinary management and high clinical suspicion are crucial for diagnosing and treating this rare condition.

## Abstract

Aseptic cyst syndrome (ACS) is a rare condition frequently associated with a systemic inflammatory response. The clinical presentation closely mimics an infection, making diagnosis and treatment challenging. The most common location of aseptic abscesses is intra-abdominal. Intramuscular involvement is highly uncommon, typically affecting muscles near the trunk. This report presents a case of a male patient who developed multiple aseptic abscesses in the hamstrings and proximal gastrocnemius (GM) muscles. The patient initially underwent surgical debridement and cyst resection, followed by intravenous antibiotic therapy. Although there was a brief period of improvement, a relapse occurred, marked by renewed pain, fever, elevated infection biomarkers, and knee joint effusion. The patient was ultimately treated with corticosteroids, followed by immunosuppressant therapy, resulting in rapid disease improvement. No recurrence was observed at the final follow-up, nine months after symptom onset. A narrative review of the literature on this topic is also included. This case underscores the importance of high clinical suspicion and a multidisciplinary approach in the diagnosis and management of ACS.