OBJECTIVE: The Thornwaldt's cyst is a lesion caused by failure in the regression of the notochord, with persistence of remaining in the posterior wall of the nasopharynx. When there is concomitant infectious process, this space is filled with liquid contents, forming a cyst. The clinical picture depends on the size of the lesion, including hearing loss and headache occiput to nasal obstruction and dysphagia. The diagnosis is complemented by computed tomography and fiberoptic. Pathological examination, a cystic lesion with epithelial lining and contents pseudostratified bright yellow fluid, thick mucus or pus. Among the differential diagnoses is persistent Rathke's pouch, mucous retention cyst, neoplasm. Its treatment is surgical, with removal and marsupialization of the cyst. CASE REPORT: A case of a patient referred to our outpatient clinic with nasal obstruction, bilateral aural fullness and hearing loss for ten years. We spent the last six months also present, dysphagia, odynophagia, and dyspnea. Oroscopy, lesion of cystic aspect bulging soft palate. In fiberoptic, we observed cystic lesion, depressing the touch and obstructing approximately 90% of the cavum. Computed tomography showed a cystic lesion contrast, no cleavage plane evident in the posterior nasopharyngeal wall, blocking the same at 90%. Surgical treatment was performed with combined access, endoscopic nasal and transoral retraction of the soft palate. The patient had complete resolution of symptoms after resection of the lesion. CONCLUSION With the routine performance of endoscopy, the diagnosis of this lesion in dimensions so exuberant became quite unusual. Accordingly, this case appears to be of great value to the publication.