Orthokeratinized odontogenic cysts presenting as a periapical lesion: report of a case and literature review

Incidental finding of orthokeratinized odontogenic cyst with unusual features

Orthokeratinized odontogenic cyst (OOC) is a rare developmental odontogenic cyst occurring in the jaw with debated etiology. It was originally believed to be a variant of odontogenic keratocyst (OKC) but is now considered to be a distinct entity. The majority of the cases occur in the third and fourth decades of life. The common site is the mandibular posterior region with a male predilection. Swelling is the most common symptom which may be accompanied by pain, although in most cases, the lesion is asymptomatic. These lesions mostly present as unilocular radiolucency often associated with an impacted tooth. They may mimic dentigerous cyst and OKC in radiologic and histopathologic presentation, however, differ in biological behavior, pathogenesis and prognosis in comparison. Hence, making an accurate diagnosis is essential. This article describes an incidental finding of OOC in a 28-year-old female during radiographic investigation for orthodontic treatment. This case showed some rare features such as multilocular radiolucency, nonkeratinized epithelium in areas of inflammation, few cholesterol clefts with giant cells, presence of dentinoid-like material and dystrophic calcification in the capsule.

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

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.

Orthokeratinized odontogenic cysts: a Spanish tertiary care centre study based on HPV DNA detection

Background

The role of human papillomavirus (HPV) in orthokeratinized odontogenic cysts (OOCs) has rarely been studied. The objective is to describe the clinicopathological findings in a series of OOCs from a Spanish population that were investigated in relation to the possible presence of HPV.

Methods

A clinicopathological retrospective analysis followed by a molecular analysis of 28 high- and low-risk HPV genotypes was performed in OOC samples of patients seen during the last 15-years in a Spanish tertiary care center.

Results

Of 115 odontogenic cysts with keratinization, 16 cases of OOCs were confirmed and evaluated. OOCs occurred predominantly in the mandible of males (mean age 36.06 ± 13.16 years). Swelling of the jaw followed by pain were the most common clinical symptoms, and 56.5% of the OOC cases were associated with an unerupted tooth. After a mean post-cystectomy follow-up of 3.8 years, only one recurrent case was observed, resulting in a verrucous cystic lesion that was considered premalignant after immunohistological examination. DNA extraction was successful from 14 of the 16 OOC cases. None of the primary OCCs or the single recurrent OOC were positive for HPV in the molecular analysis.

Conclusions

OOCs show a very limited potential for recurrence. Our results suggest that neither high- or low-risk HPV subtypes are likely to play a role in the etiology or neoplastic transformation of OOC, at least in the Spanish population.

Orthokeratinized odontogenic cyst of the mandible: A rare case report with a systematic review

Orthokeratinized odontogenic cyst (OOC) is an odontogenic cyst was initially termed as the uncommon orthokeratinized type of odontogenic keratocyst by the World Health Organization. It usually occurs in mandible. Various studies have shown that OOC has typical characteristic clinicopathologic features when compared to other developmental odontogenic lesions such as dentigerous cyst and the keratocystic odontogenic tumor (KCOT). Rare recurrence was noted after surgical removal of the lesion. The purpose of this article is to present a case of OOC arising in the posterior mandible and emphasize on differentiating it from the KCOT and dentigerous cyst.