Dermatofibroma is a common benign fibrohistiocytic lesion that usually appears as a slow-growing, firm dermal nodule with a predilection for the legs of middle-aged women. They are usually smaller than 2 cm in diameter. Many histological variants have been described. Generally, the clinical and histological diagnosis is straightforward, but differentiating it from other cutaneous tumors can be difficult in atypical cases and rare variants. Giant dermatofibroma is a rare clinical variant of dermatofibroma and less than 25 cases have been reported. It is characterized essentially by its unusually large size, which often mimics malignant tumors clinically. We first present the case of a giant hemosiderotic dermatofibroma in a 54-year-old patient, who presented with a large ulcerated mass of the left foot which was excised, and then review the literature briefly.