Abstract: PURPOSE: To evaluate the feasibility and clinical value of endoscopic marsupialization of large cystic lesions with maxillary sinusal extension. METHODS: Transnasal endoscopic marsupialization was performed in 21 patients with maxillary cystic lesions that extended to the maxillary sinus. The lesions were 3.5-6 cm in size, the patients were followed up for 18-36 months. Clinical examination, nasal endoscopy and CT scans were performed postoperatively. RESULTS: In 21 patients, the cystic lesions completely resolved both clinically and radiographically. No recurrence was observed during follow up. Within 3 months, all patients showed signs of healing and facial swelling disappeared. Three months after surgery, epithelization of the cystic cavity was found in the "window". CT scans demonstrated the cystic lesions and maxillary sinus fused into a big cavity, bone regeneration in the maxillary wall. The appearance of the maxillary sinus mucous membrane turned to normal. Followed-up CT scans revealed restoration of the maxillary sinus to almost normal condition. CONCLUSIONS: Transnasal endoscopic marsupialization can be a definitive treatment for large cystic lesions with extension in the maxillary sinus.

Key words: Maxillary sinus, Odontogenic cyst, Endoscopic surgery, Marsupialization