Orthokeratinized odontogenic cyst (OOC): Clinicopathological and radiological features of a series of 10 cases

Abstract

Background Orthokeratinized Odontogenic Cyst (OOC) is a rare, developmental odontogenic cyst which was considered in the past to be a variant of Odontogenic keratocyst (OKC) later renamed as keratocystic odontogenic tumor (KCOT). The treatment of OOC is by enucleation and the prognosis, following enucleation is excellent with a recurrence rate of less than 2%. On the other hand, OKC has a recurrence rate between 8 and 25% after enucleation. Thus it is important to differentiate between the two entities. Methods All cases reported in our section as OOC during the period 2013 to 2018 were retrieved from the surgical pathology files and slides were reviewed by the authors. All cases which met the histological criteria for OOC were included. Results A total of 10 cases were included. 70% patients were males, ages ranged from 23 to 60 years, with mean age of 38.9 years. 70% of cases were located in the mandible and 90% patients presented with swelling. Radiologically, 90% cases were unilocular, all were radiolucent lesions. Mean size was 4.0 cm. Histologically, all cases demonstrated the classic microscopic features. Follow-up was available in 8 patients. All were treated by enucleation. All 8 were alive with no recurrences over a follow-up period ranging from 7 to 62 months. Conclusions OOC has a better prognosis than OKC and needs to be differentiated from OKC due to differences in treatment and prognosis. Large majority of our cases presented with swelling and occurred in the mandibles of young males. All were radiolucent and most were unilocular. All were treated by enucleation and no recurrences occurred over follow up period ranging up to 62 months. Our findings were similar to those described in other published series.

A case report and literature review of multiple orthokeratinizing odontogenic cysts: The great mimicker

“…Histologically the key features include; a thin and regular layer of stratified squamous epithelium with orthokeratinization on the surface and prominent granular cell layer. 12,13 This was reported in the histology report for all cases of multiple OOC. OOC have an orthokeratinised epithelial lining with hypergranulosis and lamellated orthokeratin in the cystic cavity.…”

“…[8][9][10][11][12] Additionally a review of 10 cases of single OOC identified that 90% of patients presented with swelling and pus-like discharge. 13 Although, it has previously been reported that patients are asymptomatic and incidental radiographic findings, 14 it is important to be aware that patients may report symptoms.…”

“…Radiographically 87%-90% of cases showed well demarcated, unilocular, radiolucent lesions. 5,13 A systematic review on singular cases of OOC identified that 68% of cases were associated with an unerupted tooth, without resorption 3 indicating how this type of cyst has similar features to dentigerous cysts.…”

Multiple radiolucencies in the mandible: A diagnostic dilemma

“…Among the jaw cysts, OKC showed most common bilateral occurrence followed by the dentigerous cyst. [ 8 ] An extensive search identified only 21 cases of bilateral dentigerous cysts in non-syndromic patients. [ 4 ] Reported cases of bilateral radicular cyst in mandible at the posterior region are also present in literature.…”

“…[ 9 10 ] A rare case of bilateral orthokeratinized odontogenic cyst in the mandible is also reported. [ 8 ] An unusual case of multiple cysts in maxilla where the hereditary amelogenesis imperfecta caused the pulpal exposure and led to the formation of multiple radicular cysts was also reported. [ 11 ] Any lesion related to the maxillofacial region requires prime intention and primary care as such lesions if undiagnosed or untreated properly can lead to various serious manifestations of the oral and maxillofacial region.…”