An Unusual Case of Radiation-Induced Dermatofibrosarcoma Protuberans: A Rare Type of Soft Tissue Sarcoma

Introduction: Dermatofibrosarcoma protuberans (DFSP) is a rare, locally aggressive soft tissue sarcoma characterized by a low metastatic potential but a high local recurrence rate. It is typically managed with wide surgical excision, with adjuvant therapies considered in cases of inadequate margins or high-grade variants. Ionizing radiation is known to induce various malignant skin tumors, but radiation-induced DFSP is exceptionally rare, with only a few documented cases. This case report presents an unusual instance of radiation-induced DFSP, highlighting the challenges in the diagnosis and management of this rare complication following radiation therapy. The case underscores the importance of long-term surveillance in patients with a history of radiation exposure and the need for early recognition of secondary malignancies. Case Presentation: We reported a patient with an unusual DFSP in the breast, which was confirmed by immunohistochemistry (IHC). This tumor developed at the margins of the radiotherapy field 6 years after the patient underwent breast-conserving surgery and radiotherapy for breast cancer. A wide local excision was performed, and since the surgical margin was 3 cm and negative, the patient did not require radiotherapy. She now remains cancer-free for 4 years after the operation was completed. While radiotherapy has proven benefits in the treatment of breast cancer, it also carries undeniable side effects, including an increased risk of secondary cancers such as soft tissue sarcomas. Therefore, it is crucial to carefully consider the indications for radiotherapy and the volume of treatment administered. Conclusions: This case highlights the potential for DFSP to arise in patients with a history of breast cancer treated with radiotherapy. Awareness of this possibility is crucial for timely diagnosis and management. Therefore, precise consideration is crucial when deciding regarding the adjuvant radiation therapy indications, treatment volume, and radiotherapy method, as although the likelihood of developing secondary cancer is very low, it is not zero.