[Rare differential diagnosis of breast tumor. Giant cell tumor of the ribs].

We report a case of a breast tumor. As carcinoma of the breast was suspected, a biopsy was taken and a very rare osteoclastoma originating in the rib was identified. Semimalignant bone tumors tend to recur locally. The symptoms are nonspecific; the initial diagnosis is often made late. To differentiate the diagnosis, one should think about primary and secondary bone diseases and tumors of the organs of the thorax. In our case, the tumor was completely resected, including the ribs, and the defect was covered with a corium plasty. In this way, we are able to save the breast. We discuss different methods for covering chest wall defects.