Predictive factors for surgical margins in dermatofibrosarcoma protuberans: insights from a retrospective Mohs micrographic surgery analysis

The optimal surgical margin for wide local excision (WLE) of dermatofibrosarcoma protuberans (DFSP) remains controversial. This study aimed to determine appropriate WLE margins through the analysis of Mohs micrographic surgery (MMS) outcomes. We retrospectively analysed 177 DFSP patients treated with MMS from 2003 to 2023. Logistic regression identified factors associated with histologically clear margins ≥1 cm. Receiver operating characteristic analysis determined a tumour size cutoff for predicting wider margins. Larger tumour size, longer disease duration, and recurrent status were significantly associated with wider margins. Tumours exceeding 2.8 cm predicted the need for ≥1 cm margins. In contrast, a 1 cm margin was generally sufficient for tumours <2.8 cm without high-risk features (head and neck location, fibrosarcomatous change, or recurrent lesions). These findings suggest that a 1 cm margin is likely adequate for low-risk DFSP <2.8 cm, while MMS remains preferable for larger or high-risk tumours.