[Postoperative pyoderma gangrenosum and cancer of the breast. Apropos of a case].

Pyoderma gangrenosum (PG) consists of extensive necrotic ulceration with bluish and purplish red margins. This disease is often associated with ulcerative colitis, systemic, hematologic or rheumatic diseases. However post-surgical idiopathic PG can occur. One post-mastectomy case is reported. PG can first be suspected on clinical appearance and the lack of a specific etiology. PG is a diagnosis of exclusion that is made only after other possibilities have been ruled out. The treatment is surgical excision and systemic corticosteroids.