Abstract
Usually, intramuscular hydatid cysts are secondary, resulting from the spread of cysts from other areas either spontaneously or after operations for hydatidosis in other regions. We present an unusual case of a primary hydatid cyst found in the left thigh of a 35-year-old woman, presenting as an enlarging soft-tissue tumour. Ultrasound, computed tomography and magnetic resonance imaging examinations revealed a multilocular intramuscular cyst in the anterior aspect of her left thigh, and no disease at any other location. We removed the entire cyst surgically, and macroscopic and microscopic histopathological examinations confirmed the diagnosis of muscular hydatidosis. Three years after the operation there had been no recurrence. In regions where hydatidosis is endemic, a tumour in any part of the body should be considered a hydatid cyst until proven otherwise.