Extensive odontogenic keratocysts of the maxilla: Review of the literature and report of six cases

REVIEW OF THE LITERATURE The OKC is a clinically aggressive keratinizing epitheliallined cyst of the jaw. Phillipsen (1) first used the term ‘odontogenic keratocyst’, and it was described as a distinct entity by Shear in 1960 (2). Shear (2) and Pindborg and Hensen (3) subsequently documented its typical histological features. The majority of cysts grow slowly and asymptomatically at the expense of the medullary bone, and can become extensive before any clinical manifestations are apparent (4). Brannon (5) reported that 50% of all OKCs are detected as incidental findings on radiographs and the remainder are due to secondary infection. The OKC is notorious for its high recurrence rate, with reports ranging from 10% to 62% (2,3). In approximately 10% of cases OKC is associated with the basal cell nevus syndrome (4,6); rarely it is linked to the development of malignancy. OKCs account for between 3% and 11% of all jaw cysts (6,7). OKCs occur predominantly in Caucasians (5,6) and are more common in males than in females (5,6,8). There is a wide age range of patients, with a peak frequency in the second and third decades (5,6,9). OKCs found in the maxilla reportedly occur in older patients (10,11). The mandible is affected more frequently than the maxilla (ratio 2:1 to 3:1) (5,6). The majority of mandibular OKCs occur in the ramus and third molar area, followed by the first and second molar area and, lastly, the anterior mandible. In the maxilla, the third molar site is most common, followed by the canine region (2). Radiographic features typically include a well demarcated, unilocular radiolucency in bone with a distinct sclerotic margin (10). However lesions can have scalloped margins, giving a multilocular appearance that is more frequent in larger lesions (13,14). OKCs of the mandible exhibit little buccolingual expansion and may extend throughout the length of the bone. Although most have a distinct boundary of cortical bone, perforation of the cortical plates and in-