Hydatid disease of skeletal muscle is a rare entity.Liver followed ALL by lung are the most common sites of hydatid cyst.Incidence of unusual sites which include spleen, kidney, mesentry, ovary, brain, skeletal system is 7,8 %.
Skeletal Twin Bookcase Bed muscle has the lowest incidence of primary hydatid among the unusual sites.Here we report a young female with rare primary hydatid disease of left posterior thigh extending into popliteal fossa.