Odontogenic keratocystic can be misdiagnosed for a lateral periodontal cyst when the clinical and radiographical findings are similar

: Lateral periodontal cyst (LPC) and odontogenic keratocystic (OK) are two osteolytic lesions of the jaw with different local invasiveness and percentage of recurrence. The aim of this study was to highlight the attention on the differential diagnosis of these lesions that sometimes can have unexpected location and can lead doubts on diagnosis, therapy, and follow-up. A 34-year-old man presented to our department with a complaint of soft pain in the vestibular aspect of left mandibular second premolar and left mandibular first molar. Vital teeth in the left mandible, no mucosal swelling, and no drainage were observed. The CBCT showed a well circumscribed hypodensity area, extending between 3.5 and the apex of mesial root of 3.6. No displacement and no resorption of the roots were notified. Upon clinical and radiographical examination, a provisional diagnosis of LPC was made and enucleation of the lesion and histological examination were planned. Histologically, a cystic wall partially lined by a keratinizing squamous epithelium was observed. Surrounding and within the lesion, there was a chronic inflammatory infiltrate also of granulomatous type and with cholesterol clefts. Based on these findings, the diagnosis of odontogenic keratocystic was done. Radiolucent lesions in the premolar and canine region are frequently clinically and radiographically misdiagnosed. The identification of keratocyst in a location preoperatively favoring a lateral periodontal cyst should be suspected and biopsy must be considered in all cases to establish the nature of the lesion, the best surgical treatment, and the follow-up appointments.