Odontogenic keratocysts (OKCs) are locally infiltrative odontogenic cysts that are usually diagnosed during routine radiographic examinations. Therefore, it is critical that dental practitioners, in particular orthodontists, recognize and diagnose OKCs to recommend appropriate treatment. This report describes a patient whose OKC was not initially identified during orthodontic pretreatment. In addition, this report discusses the clinical and radiographic features of OKCs, as well as the differential diagnoses of these lesions.
Several lesions of the jaws, including odontogenic keratocysts, can be identified in routine radiographic examinations.
Patients with radiolucent lesions of any size should have diagnostic investigation.
Orthodontists play an important role in identifying jaw lesions.
Odontogenic keratocysts (OKCs) are odontogenic cysts characterized by locally infiltrative behavior. OKCs can occur at any age but are most common between the second and fourth decades of life. They show a predilection for males and are predominantly found in the posterior region of the mandible.
OKCs are usually incidentally discovered during routine dental radiographic examinations, frequently appearing as well-demarcated unilocular radiolucent lesions, with thin well-defined and sclerotic margins. However, depending on the size of the lesion, OKCs can also be multilocular. OKCs can penetrate cortical bone and involve adjacent structures, often increasing in size before being diagnosed. Moreover, adjacent teeth can be displaced, but root resorption rarely occurs.
Because most OKCs are identified during routine radiographic examinations, orthodontists are most likely to identify them. Furthermore, OKCs initially appear as small, unilocular, radiolucent lesions that are often difficult to identify, unless a detailed radiographic analysis is performed. This report describes a patient whose OKC was not identified during orthodontic pretreatment. In addition, it discusses the clinical and radiographic features of OKCs, and the differential diagnoses of these lesions.
A 26-year-old man visited a private dental clinic complaining of mandibular swelling that he had noticed about 2 months previously. He had undergone panoramic radiography 14 months before the orthodontic treatment, which showed a radiolucent image between the mandibular left first and second molars ( Fig 1 ). According to the patient, the orthodontic treatment had started, but no diagnosis was made. Over the course of 2 months, he complained of swelling in the same area. He was then referred to another dentist, who performed an endodontic treatment on the mandibular left first molar. After that, the enlargement remained unaltered.
On clinical examination, a painless swelling covered by normal mucosa was detected in the mandibular left posterior region ( Fig 2 ). Panoramic radiography showed a well-circumscribed radiolucent image between the mandibular left first and second molars ( Fig 3 ). Since the first molar had satisfactory endodontic treatment, the most likely diagnoses were OKC and ameloblastoma.
Under local anesthesia, an incisional biopsy was performed, and the specimen was sent for histopathologic analysis. Histologically, the cystic cavity was lined with regular parakeratinized stratified squamous epithelium, with a corrugated parakeratin surface and prominent basal cells disposed in a palisaded fashion ( Fig 4 ). These features were consistent with a diagnosis of OKC.
Subsequently, the orthodontic treatment was stopped, and only a mandibular fixed retainer was maintained. The patient underwent surgical excision of the lesion with exodontia of the mandibular left first and second molars, and curettage of the surrounding bone. Eight years after the surgical treatment, no signs of recurrence were observed ( Fig 5 ).