[Hydatid cyst of the psoas muscle]

Hydatid cysts in the psoas muscle are unusual. The authors report a case of a hydatid cyst which had developed within the psoas muscle and was detected from a mass in the left iliac fossa which was diagnosed before surgery by ultrasound and a CT scan, which remain the preferred primary examinations for the investigation of masses of this type. The authors discuss the various possible clinical and paraclinical contexts and recommend total pericystectomy of a closed cyst as the best treatment following extraperitoneal iliac surgical opening.