Orthokeratinized Odontogenic Cyst: A Report of Three Clinical Cases

The orthokeratinized odontogenic cyst (OOC) is a rare developmental odontogenic cyst that has been considered as a variant of the keratocystic odontogenic tumour (KCOT) until Wright (1981) defined it as a different entity. Surgery is the usual treatment, and recurrence or association with Gorlin-Goltz syndrome has rarely been described. In this report, we presented three cases of this pathology, and we review the principal clinical, histological, radiological, and therapeutic aspects. Case 1. A 73-year-old female presents with a slight swelling on the right mandible, associated with an unilocular well-defined radiolucent lesion. Case 2. A 27-year-old female presents with a painful mandibular swelling associated with an unilocular radiolucent lesion posterior to the 4.8. Case 3. A 61-year-old male was casually detected presents with an unilocular radiolucent lesion distal to the 4.8. Conclusion. The OOC is a specific odontogenic clinicopathological entity that should be differentiated from the KCOT as it presents a completely different biological behaviour. 1. Introduction The orthokeratinized odontogenic cyst (OOC) is a developmental odontogenic cyst relatively rare, arising from the cell rests of the dental lamina [1, 2]. It was first described by Schultz in 1927 [3] as an orthokeratinized variant of the formerly called odontogenic keratocyst, today known as the keratocystic odontogenic tumour. It is not until 1981 that Wright defines this as an independent entity [4]. Since then it has received various designations, such as “orthokeratinized variant of odontogenic keratocyst” or “orthokeratinized cyst of the mandible”. It is not until 1998 that Li et al. suggest the term “orthokeratinized odontogenic cyst,” which is the most accepted at the present time [2, 5]. The OOC occurs predominantly in males between the third and fourth decades, with a mean age of 33.5 years [2, 5]. The lesion is located mainly in the molar region and posterior mandible [1, 2]. These tumours can reach a large size that causes cortical expansion and presents as a swelling, along with pain, although in most cases it can be detected incidentally during a radiographic examination [1, 2]. Radiographically the cyst appears as a well-circumscribed, unilocular, or multilocular radiolucency that occasionally is associated with an unerupted tooth or with the root without causing resorption [1, 6, 7]. Displacement of neighbouring teeth and of the inferior dental canal has been described [5]. The histopathological analysis confirms the diagnosis which shows a cystic cavity lining composed