[Hydatid cyst of the breast. 20 cases]

Hydatid cysts of the breast are benign new growths due to Echinococcus Granulosus. This retrospective report concerns 20 cases observed at Salah Azaiez Institute of Tunis from 1969 to 1982. Hydatid cyst involves women of 30 to 50 years of age living in areas where hydatid is endemic. As they evolve slowly, clinical features do not make it easy to confuse the diagnosis with new growths but mainly with cysts in mammary dysplasia or benign tumours. Mammography is the key examination to make the diagnosis even though this is not obvious each time. Specific immunological patterns are rarely used because it is easier to diagnose hydatid by other methods. Surgical treatment is curative in all cases.