Echinococcal involvement of the breast is extremely rare and usually not included in the differential diagnosis of breast lumps. This is an unreported case of a 23-year-old woman who came for mastalgia of the right breast. The diagnosis was performed by an ultrasound exam in conjunction with MRI before surgery. A complete excision of the breast cyst either the thoracic location was performed with success. Hydatid cyst of the breast is rare. The diagnosis by fine needle aspiration is controversial. The treatment is based on complete excision of the cyst