Uncommon musculoskeletal femoral hydatid cyst disturbs a female for a year: Case report.

"Hydatid cyst" which also known as cystic Echinococcosis is a parasitic infestation caused by the larval stage of Echinococcus granulosus. The liver and lungs are the most sites to occur. Incidence in muscles is exceptionally rare. We report a case of a 36-year-old female presented with an uncomfortable mass in the upper medial of her right thigh without any presence of other symptoms. She lived in a rural area in Manbij, which is an endemic area of hydatid cysts in Syria. She was a shepherdess; therefore she had direct contact with sheep and dogs. Ultrasound examination showed a cyst located between adductor longus muscle and gracilis muscle closed to the deep femoral artery. The patient was treated with pharmaceutical therapy for a week before cystectomy, which was done under general anesthesia. The cyst was dissected between the fibers of adductor longus muscle from the lateral side and fibers of the gracilis muscle from the medial side. The cyst with all its layers was resected. Musculoskeletal Echinococcosis is a rare disease, because of intramuscular growth of cysts is restricted by muscle's contractility, the muscles are undesirable habitat for Echinococcus granulosus and because of the hepatic barrier role. Many cysts are revealed by complications such as nerve compressions, infections simulating an acute abscess or a malignant tumor. Hydatid cyst present as mass of soft tissue, particularly in endemic areas, as a result of contaminated water. MRI considered the best technique in the diagnosis.