Hard Swelling in the Back of the Lower Jaw: Odontogenic Keratocyst

Abstract

Odontogenic keratocyst (OKC) is one of the commonly encountered odontogenic cysts of the jaw. It is locally aggressive developmental cyst with propensity to recur following treatment despite its benign nature. OKCs occur in patients over a wide age range with a peak in the second and third decades of life with a male predominance. The mandible is the most common site of occurrence for OKC, and more than half of the lesions involve the posterior body and ramus of the mandible. Aetiologically, OKC is developed from remnants of dental lamina. Clinically, OKC can manifest single or multiple lesions. Early lesion is often asymptomatic, and larger lesion can cause jawbone expansion and displacement of adjacent structures. Patients with multiple lesions should be evaluated for naevoid basal cell carcinoma syndrome involvement. Radiographically, OKC presents as a well-defined unilocular or multilocular radiolucency with well-corticated margins. Histopathological features of OKCs are well characterized and pathognomonic. It exhibits uninflamed fibrous cyst wall lined by thin and regular parakeratinized stratified squamous epithelium with flat epithelium-connective tissue interface. The basal cell layer is often palisaded and exhibits hyperchromatic nuclei with reversal nuclei polarity. Daughter cysts may be found within the cyst wall. Treatment is mostly by enucleation, decompression/marsupialization followed by enucleation or resection based on clinical and radiological assessment and the anticipated potential morbidity associated with different options.