A rare benign neoplasm of cementum. It usually affects patients under the age of 25 years. It is most often associated with the apices of mandibular first molars and is not found in association with the anterior teeth. It presents radiographically as a well-defined, round radiopaque mass surrounded by a radiolucent rim, and is usually asymptomatic. The lesion obscures the lamina dura (see cementoma). Treatment is by surgical removal of the tooth and associated tumour.