We report a case of a breast tumor. As carcinoma of the breast was sus
pected, a biopsy was taken and a very rare osteoclastoma originating i
n the rib was identified. Semimalignant bone tumors tend to recur loca
lly. 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 cerium plasty. In this way, we are able
to save the breast. We discuss different methods for covering chest wa
ll defects.