The most common form of cystic lesions affecting the maxillofacial region are odontogenic cysts. It is classified into developmental and inflammatory origin, in which the developmental group includes keratocysts and dentigerous cysts and inflammatory group includes radicular cysts. The odontogenic keratocyst was first termed by Philipsen and designated by the World Health Organization as a keratocystic odontogenic tumour, now reclassified from benign odontogenic tumour to odontogenic developmental cyst due to the emergence of marked evidence of morphogenesis and biological behaviour. Its occurrence is anywhere in the jaws, but 70% of cases involve the posterior body of the mandible. It is more prevalent in males, especially in the second and third decade of life. It has characteristic histopathological and clinical features that makes this cyst special in its aggressive behavior and higher recurrence. It can also be classified on the basis of appearance as unilocular or multilocular. Smaller odontogenic keratocysts are unilocular, but larger lesion mostly associated with multilocular appearance. Multilocular odontogenic keratocysts are most commonly accompanied with syndromes, but unilocular are not. In this present case it is unilocular and not associated with syndromes. Radiographically, it appears as well-defined unilocular or multilocular radiolucency with thin radiopaque borders. Conventional radiographic imaging, such as panoramic views and intraoral periapical films, are adequate to estimate the size and determine the location of an KCOT. However, the clinical use for cone-beam computed tomography (CBCT) is increasing and provides more information about the extent and borders of the large lesions. This poster explains an atypical appearance of odontogenic keratocyst with an absence of scalloping border and septa; usually smaller lesion lesions are associated with unilocular appearance, but here is a larger lesion associated with unilocular appearance.