We report the case of a 65years old patient followed for more than 4 years for a leg ulcer in whom a rare combination of pyoderma gangrenosum with breast cancer was diagnosed. This is a rare skin disease, usually associated with systemic disease: digestive, rheumatological or malignant. The diagnosis is mainly clinical. Taking patient diagnostic management has two objectives: to eliminate other causes of skin ulcer and determine whether there is a concomitant illness that can be treated. Bacteriological swab and a biopsy should always be performed. The treatment consists of topical corticosteroids and systemic therapy with corticosteroids or immunosuppressive agents.