# Intramuscular Cyst in the Vastus Intermedius Muscle: A Rare Presentation of a Hydatid Cyst

## TL;DR

A rare case of a hydatid cyst in the thigh muscle of a 70-year-old man is reported, diagnosed through imaging and confirmed via biopsy.

## Contribution

This paper presents a rare clinical case of a hydatid cyst in the vastus intermedius muscle, expanding the known manifestations of echinococcosis.

## Key findings

- A 70-year-old male presented with a progressive thigh swelling diagnosed as a hydatid cyst.
- Imaging and biopsy confirmed the presence of a hydatid cyst in the vastus intermedius muscle.
- Surgical excision was performed, and the patient's diagnosis was confirmed post-operatively.

## Abstract

Echinococcosis, or hydatid disease, is a parasitic infection caused by a cestode from the Taeniidae family, mainly by Echinococcus multilocularis or granulosus. It is predominantly seen in the lungs or the liver. The hydatid disease rarely manifests as a palpable mass in the muscles. This study reports a case of a 70-year-old male who has presented with a swelling in the anterolateral aspect of his right upper thigh, which was progressive over the past two years. The swelling was initially painless and is now associated with pain. The clinical diagnosis of an abscess was suspected. The diagnosis of his swelling was later made as a hydatid cyst in a muscle of the thigh based on the imaging modalities, the ultrasound, and an MRI. The patient underwent surgical excision of the cyst, following which the diagnosis of a hydatid cyst was confirmed on the biopsy.