Durable control of recurrent dermatofibrosarcoma protuberans using wide-margin Mohs micrographic surgery and flap reconstruction without adjuvant radiotherapy: a case report and literature review.

Background: Dermatofibrosarcoma protuberans (DFSP) is a rare, locally aggressive cutaneous sarcoma characterized by a high risk of local recurrence and minimal metastatic potential. However, it remains unresolved whether adjuvant radiotherapy (RT) is necessary in all cases of resectable recurrent disease when complete histologic margin clearance is achieved. Case presentation: A 41-year-old man presented with a localized recurrent DFSP after a prior wide local excision with reportedly negative margins. He underwent Mohs re-excision with 3-cm peripheral margins extending to the fascia, followed by flap reconstruction. Intraoperative frozen-section analysis confirmed microscopically negative margins. No adjuvant RT or systemic therapy was administered. Over a 4-year follow-up period, including serial MRI, no evidence of further recurrence or metastasis was noted. Clinical discussion: This case illustrates durable local control of recurrent truncal DFSP achieved solely through Mohs re-excision with confirmed negative margins and no adjuvant therapy. These findings indicate that durable oncologic control can be achieved through meticulous re-excision alone, and escalation to adjuvant RT is not invariably required in carefully selected patients if negative margins are reliably secured. Additionally, flap reconstruction enabled wide resection while optimizing cosmesis and function compared with skin grafting. Therefore, potential treatment-related morbidity can be avoided without compromising oncologic outcomes. Conclusion: Mohs micrographic surgery re-excision with confirmed negative margins achieved sustained local control over 4 years in recurrent truncal DFSP. The outcome supports individualized surgical management without adjuvant RT in selected resectable recurrent cases. Margin adequacy might serve as the primary determinant of local control while avoiding long-term radiation morbidity.