Early Arising Sarcoma After Adjuvant Radiotherapy for Oral Squamous Cell Carcinoma.

Radiation-induced sarcoma of the head and neck (RISHN) is a rare and long-term complication of radiation therapy (RT). This report describes a case of RISHN characterized by early and insidious onset. An 80-year-old man was surgically treated for advanced oral squamous cell carcinoma of the left retromolar trigone (pT4aN0). Sixteen months after completion of adjuvant RT, an exophytic sessile lesion arose in the left border of the soft palate. Histologic assessment showed a malignant neoplasm with spindle-shaped cells and areas of bone matrix without perivascular or perineural invasion; such features in addition to immunohistochemical assessment (negative for pan-cytokeratin; positive for vimentin; negative for epithelial membrane antigen; negative for p63; Ki-67, 30%) are consistent with poorly differentiated sarcoma (cT1aN0M0). Fifteen months after a wide surgical resection, the patient was free of disease. RISHN is usually an aggressive neoplasm with insidious onset. Nevertheless, early diagnosis followed by complete surgical excision could make the prognosis comparable to that of spontaneous sarcoma.