Pyoderma gangrenosum is a skin disease of unknown etiology and often occurs in association with a systemic disease. Characteristic features of pyoderma gangrenosus are painful chronic ulcers. We describe the case of 77-year-old cardiopathic patient with a large ulcer of the lateral side of the right knee associated with ulcerative colitis. Another typical lesion was observed in the gluteal furrow. Furthermore on the pubis, at the side of a recent surgical scar an ulcerative lesion occurred. Laboratory investigations for the immunological asset revealed no significant alterations. Moreover the patient presented an active inflammatory bowel disease. This case is of interest for the synergism of the cutaneous lesions and the inflammatory bowel disease in this pathologic process and for the rapid and fatal course of the disease. Another interesting feature of this case is the pathergy which appared on a previous surgical scar of the pubis.