Adult soft tissue sarcomas of the hand are rare, representing approximately 2% of upper extremity tumors. Their indolent growth often leads to misdiagnosis and treatment delays. While amputation has traditionally been the standard approach, advances in limb-sparing techniques, supplemented by radiotherapy, have improved local control and functional preservation. However, radiotherapy in hand sarcomas carries significant risks, including impaired wound healing, fibrosis, stiffness, edema, fractures, and, in rare cases, necrosis and radiation-induced sarcomas. This case-based narrative review is built around an institutional case: an 81-year-old woman with recurrent leiomyosarcoma of the left hand who developed graft necrosis following radiotherapy after R2 resection. Despite initially favorable outcomes, the patient experienced severe skin graft complications, leading to functional impairment and the need for additional wound management. A comprehensive narrative literature review of hand sarcomas treated with radiotherapy highlights the challenge of balancing effective tumor control with minimizing adverse effects. While radiotherapy provides high local control rates, particularly in cases with residual disease, complications such as graft necrosis, as reported here, can significantly affect functional outcomes. The review emphasizes the importance of achieving clear surgical margins, as even modern radiotherapy techniques like volumetric modulated arc therapy (VMAT) guided by stereotactic equipment may fail to prevent complications. Long-term follow-up remains essential to detect and manage late sequelae, with the aim of restoring any compromised function. This case underscores the need for careful patient management and the difficult benefit/risk trade-off associated with radiotherapy when surgery alone is insufficient.