Development of Malignant Peripheral Nerve Sheath Tumor After Keloid Treatment.

A malignant peripheral nerve sheath tumor is a rare and aggressive soft-tissue sarcoma that originates from Schwann cells or neural crest cells. Although 60% of cases are associated with neurofibromatosis type 1, approximately 10% occur secondary to radiotherapy. We report a malignant peripheral nerve sheath tumor that developed after radiotherapy for a keloid. A 35-year-old woman presented with a 7 × 9 cm left shoulder lesion 11 years after surgical treatment of a keloid followed by radiotherapy (20 Gy). Four years earlier, she had undergone a second operation with postoperative radiation (25 Gy) to address keloid recurrence. Biopsy was concerning for malignancy, the tumor was resected with a 2-cm margin, and reconstruction was performed using a latissimus dorsi flap. The lesion exhibited erosion and hemorrhage not seen in benign keloids, and histological examination of the surgical specimen revealed high-grade sarcoma. No recurrence has been observed during follow-up. The development of secondary malignancy after radiotherapy for keloids is exceedingly rare-only 6 cases have been reported, including ours. However, clinicians must be vigilant in all keloid patients undergoing radiotherapy. Rapid enlargement, erosion, or bleeding in previously treated keloids should raise suspicion for malignant transformation. Proper radiation protocols and protective measures are essential to mitigate the risk. Early recognition and surgical intervention are critical for achieving favorable outcomes.