Appearance of Recurrent Dermatofibrosarcoma Protuberans in post-operative MRI follow-up

Abstract Purpose To analyze the appearance of recurrent dermatofibrosarcoma protuberans (DFSP) in post-operative MRI follow-up and to assess the occurrence of post-operative soft-tissue changes detected in MRI. Methods 464 MRI follow-up scans of 32 patients with histologically proven diagnosis of DFSP were analyzed. MR imaging was performed using a 1.5T MRI system. Recurrent DFSP was examined for signal intensity, contrast behavior, appearance and extent in MRI. Results The mean age of the patients was 44,5±17,1 years. Recurrences of DFSP occurred 26±23,3 months after primary tumor resection in the mean (Min.: 9, Max.: 60). In 25% of the patients (n=8) recurrences of DFSP were detected. Recurrent DFSP most often showed a nodular and homogenous configuration with well-defined borders and marked contrast enhancement, as well as a hyperintense signal in PD-weighted and TIRM sequences. All recurrences were well detected in the follow-up MRIs, regardless of the performed plastic surgical procedure. Lateral and depth margins had no significant impact on the local recurrence rate. 86% of the patients developed subcutaneous tissue edema (p Conclusion Recurrent DFSP mainly appear uniform and clearly delimitable on MRI as nodular, homogeneous and well-defined lesions with marked contrast enhancement. Therefore MRI is a valuable tool for post-surgical follow-up. Nearly all patients develop subcutaneous edema after resection of DFSP.