Hydatid Cyst in the Lumbar Paravertebral Muscle: A Case Report.

A hydatid cyst is a zoonotic disease caused by the worm Echinococcus granulosus. In endemic regions, it is a well-known differential diagnosis of cystic lesions, especially in the liver, lungs, brain, and vertebral column. Primary paravertebral muscle involvement, however, is rarely reported. In the current report, we present the case of an 11-year-old girl complaining of back pain with a well-defined single cystic lesion in her lumbar paravertebral multifidus muscle evident in imaging studies. The patient had no concomitant lesion in her systemic evaluation. The cyst was resected totally with its daughter cysts, and the pathology confirmed the diagnosis of a hydatid cyst. Although the paravertebral muscle is an extremely rare site of infection for a hydatid cyst, it should be kept in mind in mass lesions with a cystic nature.