The WHO in the year 2005 reformed the nomenclature of odontogenickeratocyst (OKC) to Keratocysticodontogenic tumour (KCOT) as it always has been recognised with alarming interest because of its strange nature, argued expansion phenomenon, distinctive propensity for neoplastic behaviour, recurrence and unclear treatment regimens. These lesions have been the topic of intense study over the last decade. Here, we present a case of a 30 year old man with an extensive osteolytic lesion in the body of the mandible extending right up to the coronoid process. This patient underwent multiple consultations previously, however remained symptomatic. The incisional biopsy was non-contributory. The histological examination of the excised specimen gave a diverse picture of a bony pathology but finally was conclusively established as a KCOT, by the presence of characteristic cystic lining in only one end of a section. The case has been deliberated with the clinical, radiological and histopathological parameters.