Radicular cyst in a primary tooth showing numerous Malassez-type epithelial rests: An immunohistochemical study

Abstract

Introduction: The radicular cyst is an odontogenic cyst of inflammatory origin, derived from the epithelial rests of Malassez present in the periodontal ligament, usually as a consequence of pulp necrosis. It is the most common type of odontogenic cyst, with a prevalence ranging from 52% to 68%. However, its occurrence in primary dentition is rarely reported. Some studies indicate that, in periapical inflammatory processes of deciduous teeth, radicular cysts are more frequent (73.5%) than granulomas. Despite the established relationship between Malassez rests and the pathogenesis of radicular cysts, their presence is seldom mentioned in the literature, even in permanent dentition. Case Report: An 8-year-old male patient underwent extraction of tooth 85 due to extensive caries, pulp necrosis, and an inter-radicular lesion. Histopathological analysis revealed a radicular cyst with abundant Malassez-type epithelial rests within the cystic capsule and periodontal ligament space. Immunohistochemical analysis showed positivity for pan-CK AE1/AE3, CK19, p63, and p40 in the cyst epithelium and epithelial rests, with slight positivity for vimentin. Conclusion: The presence of radicular cysts in deciduous dentition remains underreported. This case reinforces the association between Malassez epithelial rests and cyst pathogenesis, as demonstrated through morphological and immunohistochemical analyses.