Advanced Pyoderma Gangrenosum Previously Treated as Squamous Cell Carcinoma.

Pyoderma gangrenosum is a rare, neutrophilic ulcerative skin disease of unknown etiology often associated with an underlying systemic disease. We present a case of a pyoderma gangrenosum that was initially misdiagnosed and treated as squamous cell carcinoma in another hospital. Multiple surgical treatments triggered postoperative exacerbations and further rapid progression of the lesions. History of pathergy, clinical findings, and histopathological features examined at our Department indicated pyoderma gangrenosum. The diagnosis was confirmed by excluding other diseases that could cause similar-appearing cutaneous lesions. No associated underlying disease was determined. After the diagnosis was confirmed, corticosteroid therapy was initiated until complete remission of ulcerations.