Myofibrosarcoma of the maxillary sinus with orbital floor involvement: a case report.

Myofibrosarcoma is a rare spindle-cell malignancy with myofibroblastic differentiation, and primary maxillary sinus involvement is exceptional. A 36-year-old woman presented with progressive unilateral nasal obstruction, purulent rhinorrhea, and hemifacial pain. Computed tomography and magnetic resonance imaging demonstrated a destructive 44 × 45 × 57 mm right maxillary sinus mass involving the orbital floor and extending into the nasal cavity, ethmoid cells, and pterygopalatine fossa. Histology and immunohistochemistry supported the diagnosis of myofibrosarcoma. Partial maxillectomy with titanium orbital floor reconstruction was performed. Several soft-tissue margins were positive, whereas gingival and bony margins were clear. Postoperative radiotherapy delivered 66 Gy in 33 fractions. This case illustrates the diagnostic complexity of sinonasal spindle-cell tumors and the individualized role of radiotherapy when local control is threatened by anatomically constrained positive-margin disease.