Introduction
Odontogenic Keratocysts are benign lesions, limited to a particular region and aggressive type of developmental cysts.1, 2 The term Odontogenic Keratocyst (OKC) was first given in 1956 by Philipsen. Initially it was considered as a developmental odontogenic cyst of jaw by WHO in 1981 & 1992.3 It was redefined as Keratocystic Odontogenic Tumor (KCOT) in the WHO classification of 2005.4 In 2017, the WHO re-classified OKC back into the cystic category. 1, 5
Case History
An old male patient of 36 years reported with chief complaint of swelling and pain in the upper front tooth region since 6 months. Patient gave history of trauma to the anterior tooth 2 years back. Patient noticed a swelling in the same region six months back which grew gradually to the present dimension. Swelling was interconnected with mild pain which aggravated on applying pressure over the swelling.
A solitary well defined ovoid shaped swelling was noted in the anterior hard palate. Rugae appeared stretched with deviation of the midpalatine raphae towards the left side. On palpation, swelling was tender, fluctuant and firm in consistency (Figure 1). Considering these features, we arrived at a clinical or provisional diagnosis of infected periapical cyst in relation to the traumatized maxillary central incisors.
Figure 2
A solitary well defined radiolucency with scalloped corticated borders in relation to the apex of maxillary central incisors
Figure 4
6-8 cell layers thick stratified squamous epithelium with corrugated surface and keratin pearls
On electric pulp vitality test the left central incisor was non vital. A solitary well defined radiolucency with scalloped corticated borders in relation to the apex of maxillary central incisors was noted in maxillary occlusal radiograph (Figure 2). CT sections illustrated well defined hypodense area in the anterior hard palate with scalloped borders (Figure 3a&b). Histopathological examination of incised biopsy specimen showed a 6-8 cell layers thick stratified squamous epithelium with corrugated surface and keratin pearls (Figure 4). Considering all these features we arrived at a final diagnosis of Infected Odontogenic Kerotocyst of Anterior Maxilla. Excision of the lesion was done completely with extraction of left central incisor and diagnosis was confirmed further. Patient has been re-viewed over a period of one and half year with no evidence of recurrence (Figure 5).
Discussion
The odontogenic keratocyst (OKC) has been reclassified from tumor to an odontogenic cyst. 1, 6 Odontogenic keratocyst (OKC) is named because of the keratin which is produced by the cystic lining. These are derived from dental lamina remnants.7, 8 Toller suggested that the OKC must be considered as a benign neoplasm rather than a conventional cyst by its clinical behaviour.9 OKC is locally destructive in nature and highly recurrent characteristic.2
It can be seen in any age group with peak age of second to fourth decade, with slight male predilection. 1 The prevalence of OKC in maxillary anterior region is only about 13%.7 These lesions tend to grow in an anterioposterior direction within the medullary cavity of bone without causing obvious bone expansion.9 Mandibular cyst crosess the mid line and maxillary cyst involve sinus and nasal floor, premaxilla and maxillary third molar region.1 Radiographically these lesions show unilocular or multilocular radiolucency. Resorption of the approximated roots and displacement is more common. An important characteristic of the OKC is its propensity to grow along the internal aspect of the jaws, causing minimal expansion.10 Microscopically it is characterized by a parakeratinized surface which is typically corrugated rippled or wrinkled with a prominent palisaded, polarized basal layer of cells often described as having a ‘picket fence’ or ‘tombstone’ appearance. 11, 12 Its epithelium is thin and mitotic activity is frequent. The lumen of the keratocyst may be filled with a thin straw colored fluid or with a thicker creamy material. 11, 12 Sometimes the lumen contains a great deal of keratin. It has less Cholesterol, as well as hyaline bodies at the sites of inflammation.12 The reclassification of OKC as an odontogenic cyst encourages the choice of conservative treatments and reinforces the continuity of investigations on decompression and complementary treatment. 6 In the present case, lesion was located in the maxillary anterior periapical region and was associated with non-vital tooth and misdiagnosed as a periapical cyst.
