[Pyoderma gangrenosum and breast cancer: a new case].

We report here a new case of pyoderma gangrenosum (PG) associated with a breast cancer in a 39-year-old woman. We only found in literature three other reports of this rare entity which seems usually to be associated with monoclonal gammopathy, gastro-intestinal diseases such as Crohn's disease, chronic ulcerative colitis, leukemias or rheumatologic diseases. A commun hapten between of tumor and skin may explain the origin of this inflammatory lesion. In our case, PG could be a paraneoplastic syndrome.