Primary Hydatid Cyst of the Trapezius Muscle: An Unusual Location and Review of the Literature.

Hydatidosis is a cosmopolitan anthropozoonosis common to humans and many mammals, caused by the development in the body of a dog tapeworm called Echinococcus granulosus. As accidental intermediate hosts, humans contract the infection either directly through contact with dogs or indirectly by ingesting contaminated food. They represent an epidemiological dead-end. Hydatid cysts are typically associated with the liver and lungs and, more rarely, with bones, the brain, eyes, heart, kidneys, and spleen. We present an unusual case of a hydatid cyst located in the trapezius muscle of a 76-year-old woman. Clinical, biological, and radiological data allow us to evoke the diagnosis and avoid an inopportune puncture. Treatment was exclusively surgical, with the removal of the cyst without cyst breach.