Dermatofibrosarcoma protuberans (DFSP) is a rare dermal tumor of intermediate malignancy with a locally aggressive growth behavior with a high rate of recurrence. Wide local excision with histographic margin control as well as regular follow-ups including clinical as well as ultrasound examination are crucial to detect local recurrence or metastasis. Ultrasound imaging can not only identify recurrences but also asses their extent. We report on a patient with a relapse of fibrosarcomatous DFSP, which could be demonstrated by ultrasound imaging.