A digital manual for the early diagnosis of oral neoplasia
Periapical (radicular) cyst
Periapical cyst is the most common odotogenic cyst occurring in relation to the apex of a non-vital tooth. This develops as sequelae of inflammation of the pulp of the non-vital tooth leading to the formation of a granuloma around the apex of the involved tooth, which can undergo necrosis and lead to the formation of a cyst. This cyst is often asymptomatic, and when it is large it can appear as a swelling. The cyst is painful if it is infected. Radiographically the lesion appears as a sharply circumscribed radiolucent lesion in relation to a non-vital tooth.
Generally the cyst resolves following endodontic therapy of the involved tooth. However, if the lesion fails to resolve, the cyst should be surgically removed and histopathologically examined, as squamous cell carcinoma occasionally arise de novo in these cysts.
Figure 1: Periapical cyst. Note the cystic, fluctuant swelling on the hard palate and the severe attrition of the incisal edges of the maxillary anterior teeth.