Pyoderma gangrenosum: a clinical manifestation of difficult diagnosis.

Pyoderma gangrenosum is an uncommon ulcerative cutaneous dermatosis associated with a variety of systemic diseases including inflammatory bowel disease, arthritis, hematological malignancies, hepatitis and acquired immunodeficiency syndrome (AIDS). The pathogenesis of pyoderma gangrenosum remains unknown. Its diagnosis is usually based on clinical evidence and confirmed through a process of elimination of the other possible causes of cutaneous ulcers. This report describes a case of pyoderma gangrenosum with extensive ulceration that responded well to treatment.