Giant Radicular Cyst Involving the Maxillary Sinus

The most prevalent cystic lesions in the jaws are radicular cysts. They are made up of epithelial remains that multiply after pulp necrosis due to inflammation. Radicular cysts rarely grow to substantial sizes, while typically being tiny and asymptomatic. When localized, they are treated with root canal treatment; when large, they are treated with surgical procedures. A 28-year-old systemically healthy male patient was admitted to our clinic due to extraoral swelling in the right maxillary posterior region. Radiographic examination revealed a well-defined lesion localized in the right maxillary region, extending into the nasal cavity and orbital floor, including the maxillary sinus. The lesion, in which cyst fluid was observed as a result of aspiration biopsy, was enucleated under general anesthesia and an excisional biopsy was performed. The biopsy confirmed the preliminary diagnosis of the radicular cyst. Radicular cysts seen in the maxillary region may resorb adjacent anatomical structures and develop into the sinus. Such lesions should be diagnosed before they reach large sizes and the causative teeth should be treated.