"Marjolin's ulcer" is known as malignant degeneration of ancient burn scars, but both words can induce misdiagnosis. Malignant degeneration of scarring tissue can occur and can vary in its clinical, histological manifestations and its pre-existing skin lesions. We present several cases to substantiate our observations. "Marjolin's ulcer" is not synonym to an ulceration appeared on an old burn scar, transformed into squamous cell carcinoma.