Objective:Try to analyze the clinical and pathological characteristics in patients with transformed dermatofibrosarcoma protuberans (DFSP) and discuss the standard surgical treatment and combined treatments for them. Methods:Medical charts of 34 patients with histologically confirmed transformed DFSP treated between January 1985 and December 2006 in Cancer Hospital of Fudan University were submitted to a retrospective study. Results:Among the 34 cases,32 had high grade fibrosarcomatous change (DFSP-FS) and 2 had malignant fibrous histiocytoma change (DFSPMFH).Compared with classical DFSPs,these transformed DFSPs had significantly higher recurrence rate after wide excision (P<0.0001),and the sizes of the recurrent tumors were larger (P=0.009),the durations of recurrence were shorter (P=0.012).Also they had higher metastatic rate (P<0.0001) and worse survival rates (P<0.0001). Conclusion:Transformed DFSPs are more aggressive tumors which need more active treatments.In order to reduce the local recurrence rate and decrease the degeneration into more malignancy caused by multiple local recurrences of the tumor,adequate initial resection and standard wide excision are more important for patients with transformed DFSPs.Combined treatments including adjuvant radiotherapy may be an optimal therapeutic strategy.