Hydatid cyst disease is one of the zoonoses caused by the larval stage of Echinococcus granulosus,mostly involving the liver and the lungs; but its complications can be seen in every site andorgan. Sometimes it can cause suspicious and complicated cases that mimic malignancy. Forinstance, axillary involvement of hydatid cyst is very rare. It is important to differentiate hydatidcyst disease from cancer, since it may show malignant features when pulmonary or other distantorgan involvement takes place. In this study, we present a case of multiple masses in the lungsand the axillary region in a 48-year-old woman. The ultrasonography was unable to detecthydatid cysts. Biological values were normal except for serum sodium (Na) and potassium (K);and enzyme-linked immunosorbent assay (ELISA) test was negative. Hydatid cyst was diagnosedwhile taking a biopsy from the axillary tumor.