A distinctive form of paradental cyst can occur on the buccal and apical aspects of erupted mandibular molars. This cyst has peculiar clinical and radiographic features, although the microscopic findings are the same as those of odontogenic inflammatory cysts. Diagnostic and therapeutic problems can occur when this lesion is misinterpreted as a radicular cyst. The purpose of this paper is to present an additional case of a paradental cyst in the buccal and mesial aspects of a mandibular second molar involving the apical area of a mandibular first molar. The difficulty of diagnosis, treatment, and controversies regarding terminology are also discussed.