Radicular cysts are the commonest type of odontogenic cyst. Endodontic treatment is recommended for the majority of them, but an open excision is recommended for a huge one. A 28-yearold man presented with a palatal mass that had been present for one week. Computed tomography and intraoral dental radiographs demonstratedthe presence of a radicular cyst. The lesion had invaded the hard palate and the left maxillary sinus and therefore a neoplasm was also suspected. He received endodontic treatment and apical closure followed by an open excision using a sublabial approach. The cyst was totally enucleated after the frozen section had been reported to be simply a cyst. Over the following nine months the palatal mass did not recur, but a defect of the hard palate could be palpated.