Primary hydatid cyst of the biceps femoris.

Echinococciasis is a zoonotic infestation, which generally involves the liver and the lungs. Primary muscle hydatidosis is an uncommon finding. The authors report a case of primary hydatid cyst localized in the right long head of the biceps femoris of a 25-year-old woman. A wide excision of the cyst with a safety margin was performed. No recurrence has been detected after a 3-year follow-up period. The authors review the literature and discuss the MRI findings. The diagnosis of muscular hydatid cyst is done using clinical and radiological findings in endemic context.