Abstract
BACKGROUND: Fibrosarcoma is a rare, invasive soft tissue sarcoma that is more common in males aged 30-60 years. It accounts for 1% of all malignancies in the human body. Treatment is radical surgical removal, radiotherapy, and chemotherapy. CASE PRESENTATION: A 58-year-old Khorasani Persian male patient with a complaint of expansion, pain, and paresthesia in the left maxillary quadrant was diagnosed with infiltrative high-grade sarcoma. Tumoral cells were strongly diffuse positive for vimentin and negative for S100 and desmin, indicating high-grade adult fibrosarcoma. CONCLUSION: This report presents a rare case of a fibrosarcoma causing paresthesia, pain, and expansion in the maxilla with maxillary sinus invasion, which requires early diagnosis and immediate referral.