A diagnostic dilemma: endodontic lesion or odontogenic keratocyst? A case presentation

Aim  To present a clinical case of odontogenic keratocyst (OKC) simulating a lateral periodontal cyst.
Summary  A 39-year-old female complaining of swelling and pain in the left mandibular premolar area was found to have a radiolucent lesion between teeth 34 and 35 (FDI). Both teeth had incomplete root fillings, and orthograde re-treatment of both premolars was performed. At 2-year follow-up, radiographic examination showed an increase in the radiolucent defect with respect to the previous examination. A surgical treatment of tooth 34 was then performed, with histological examination of the lesion. Histological features were consistent with an OKC, and the lesion was successfully treated by complete enucleation and application of Carnoy's solution. At 2-year follow-up, no clinical signs or symptoms were found and the radiolucent area had disappeared.
Key learning points • Odontogenic keratocysts may mimic endodontic lesions.
• Clinicians should carefully review their cases and consider surgical intervention with biopsy in cases that do not heal.     

Peculiar case of orthokeratinised odontogenic cyst: a peripheral counterpart of the intraosseous entity?

We describe a case of an orthokeratinised odontogenic cyst (OOC) in a 49-year-old man, which presented as a submucosal fluctuant, non-tender, soft nodule distal to the inferior right first molar that could be considered a peripheral counterpart of the intraosseous OOC.     

Keratocystic odontogenic tumour (KCOT)—a cyst to a tumour

Purpose

The World Health Organization (WHO) has reclassified ??odontogenic keratocyst?? (OKC) to ??keratocystic odontogenic tumour?? (KCOT) in 2005. Currently, this tumour is classified as a benign neoplasm of odontogenic origin and not as a cyst. This article reviews and discusses history, classification scheme, aetiology and pathogenesis, molecular and genetic basis, incidence, epidemiology and site, clinical features, imaging, histopathology, immunohistochemistry, treatment options, prognosis, recurrence and malignant transformation of KCOT, with emphasis on understanding the basis of reclassification as ??keratocystic odontogenic tumour??.

Methods

A systematic search and review of the literature was carried out in the online database of the United States National Library of Medicine to identify eligible titles for the study.

Results

Current evidence suggests that the scientific community still continues to use the term ??odontogenic keratocyst?? more favourably than ??keratocystic odontogenic tumour??.

Conclusion

The online database search indicates that the scientific community still continues to use the term ??odontogenic keratocyst?? more favourably than ??keratocystic odontogenic tumour??. At this juncture, where the terminology has changed from a cyst to a tumour, a thorough review of literature on KCOT is presented.     

A series of 240 odontogenic keratocysts: Should we continue to use the terminology of ‘keratocystic odontogenic tumour’ for the solid variant of odontogenic keratocyst?

Most of the odontogenic keratocysts show an indolent behaviour like non-neoplastic lesions. For this reason, the odontogenic keratocyst was reclassified within the odontogenic cysts category in the WHO 2017 classification. Some odontogenic keratocysts may contain satellite cysts or solid squamoid islands within their wall. Recently, a solid form of odontogenic keratocyst has also been described which is composed entirely of multiple epithelial islands and small cysts in a collagenous stroma. The true nature of this variant is unclear yet.In this article, we present a series of 204 odontogenic keratocyst cases. Clinical and histologic findings of the cases in this series were described. These were also categorised according to the presence of satellite lesions. Additionally, the features of two cases of the solid form of odontogenic keratocysts were compared with those of the previous reports and other histologically similar odontogenic lesions. Current evidence suggests that this variant may be neoplastic and it differs from other odontogenic keratocysts, at least histologically. We believe diagnosing a solid lesion as a cyst is counterintuitive and the term “keratocystic odontogenic tumour” better describes this particular variant.     

Adenomatoid dentinoma or adenomatoid odontogenic hamartoma: what is the better term to denominate this uncommon odontogenic lesion?

We report two cases of an uncommon odontogenic lesion, previously described as adenomatoid dentinoma. They were well-circumscribed unilocular radiolucent lesions exhibiting discrete radiopacities, located in the left mandibular third molar region. Microscopically they were composed of odontogenic hard and soft tissues, similar to a dental germ. Dental papilla and dentin were easily identified. Odontogenic epithelium formed adenomatoid-like structures, and by scanning electron microscopy a layer of enamel was seen in contact with the dentin. Based on these clinical, radiographic, histological and electron microscopical features we proposed the diagnosis of adenomatoid odontogenic hamartoma. Treatment consisted of surgical removal, and no recurrence was observed. In our opinion all similar cases previously reported pertain to the same spectrum of this lesion and thus should be named as suggested above. Moreover, ultrastructural observations using 5 microm sections can be useful to better characterize the presence of hard tissues.     

Secretory cells in adenomatoid odontogenic tumour: tissue induction or metaplastic mineralisation?

Objective:  To undertake a detailed histological investigation of a large series of adenomatoid odontogenic tumours (AOT) to document the frequency and histomorphology of secretory cells which might indicate an inductive capacity.
Materials and methods:  Haematoxylin and eosin stained sections of 51 cases of AOT were reviewed. Selected cases were stained with periodic acid-schiff (PAS) and Congo red.
Results:  In five cases, secretory structures with a circular arrangement of tall columnar cells secreting enameloid-like matrix material were identified. Such structures have only very rarely been identified in AOT and their frequency, distribution and morphology have not been adequately documented.
Conclusions:  We have documented the presence of tall secretory columnar cells, arranged in a circular configuration actively secreting enameloid-like material and believe that such an ordered arrangement of secretory cells is more likely a result of tissue induction rather than metaplasia. The origin of these secretory structures from the pseudo-ductular component is unlikely but cannot be ruled out.     

The rubber dam, a problem for the dentist or the patient?

Although the advantages of rubber dam use are obvious and rubber dam use is established standard of care in many disciplines, its application in general dental practice is low. To assess whether a negative attitude of patients might be the case, 304 patients were asked by means of a questionnaire comments on their treatment under rubber dam. The majority of the patients experienced no hinder, excepted for rubber dam restricting the communication with the dental practitioner. Women experienced more often than men anxiety, whereas smokers more frequently experienced discomfort.     

An unusual case of heminasal aplasia: proboscis lateralis or cystic teratoma?

Unilateral aplasia of the nose is a rare congenital malformation. It is often associated with other malformations of the facial region, including abnormalities of the eye and lacrimal system, proboscis lateralis, and facial bone malformations. The authors present a case of heminasal aplasia in a 4-year-old boy who underwent surgery immediately after birth because of right-sided proboscis lateralis. A huge hemispheric tumefaction was occupying a large part of the right orbit, medial canthus, and frontonasal region of the face, causing lateroinferior protrusion of the eyeball. The right half of the external nose was aplastic. The patient was operated on by an external approach. The pathohistological findings from the top of tumefaction revealed cystic teratoma. The possible backgrounds for the onset of the tumefaction are discussed in two main directions: the cystic form of the regrowth of the remnants of inadequately excised proboscis lateralis and cystic teratoma of the ethmoidal sinus.     

Fourteen-year study of the management of the odontogenic keratocyst. Are adjunctive therapies all they are cut out to be?

Odontogenic keratocysts (OKC) are benign, developmental, locally-aggressive odontogenic cystic lesions with a high risk of recurrence. As such, the most effective treatment modalities remain controversial. The mainstay of treatment remains enucleation with or without decompression. The use of adjunctive therapies is widely reported. Our aim was to review our experience of OKCs and therefore identify the treatment modality, if there is any single one, with the lowest rate of recurrence. We also aimed to identify any common themes linking those patients experiencing cystic recurrence. Data were collected on 50 patients treated at UHCW NHS Trust over a 14-year period (2005-2018) via an anonymised database. Surgical pathways were analysed, including details of the location of the cysts and the use of adjunctive therapies, namely; mechanical debridement, cryotherapy, and the use of Carnoy’s solution. Fifty-six keratocysts, both primary (91%, n = 51) and recurrent (9%, n = 5) were included. A total of 6% of patients had a pre-existing diagnosis of Gorlin-Goltz Syndrome (n = 3). Enucleation was performed in an approximately 3:1 ratio to decompression with secondary enucleation (n = 41:15). Twenty-seven percent of patients had adjunctive therapies (n = 15). There was a 12% recurrence rate (n = 6) found only within the group of primary cysts that had been enucleated only. Notably, there were no recurrences in those cysts that had undergone adjunctive therapy. None of the cysts that underwent initial decompression or marsupialisation recurred. Following surgical intervention, no tertiary recurrent cysts were detected postoperatively. This study demonstrated the advantage of establishing a correct diagnosis prior to definitive treatment. Initial decompression in selected patients followed by enucleation, along with adjunctive therapies showed a benefit in reducing recurrences. However, in the absence of high-quality evidence for the most effective management of odontogenic keratocysts, finding a common approach will remain controversial.     

How effective is 5-Fluorouracil as an adjuvant in the management of odontogenic keratocyst? A systematic review and meta-analysis

Odontogenic keratocyst (OKC) is known for its benign but aggressive clinical behaviour, and presents a challenge in its management due to high recurrence rate following surgical intervention. The sourcing of Carnoy’s solution, the widely used adjunct in OKC treatment, has lately become difficult especially after its banning by the United States Food and Drugs Agency (FDA). This has generated interest in exploring alternative chemical agents such as 5-Fluorouracil (5-FU) and Modified Carnoy’s solution (MCS). We conducted a systematic review and meta-analysis to assess the effectiveness of 5-FU as an adjunct following surgical intervention of OKC. A protocol was registered in PROSPERO prior to the literature search. All studies reporting the use of 5-FU in OKC treatment were included in the initial search of multiple literature databases. Of the 148 initially identified articles, three met the criteria for the final appraisal. The relevant data were extracted and a meta-analysis was undertaken in relation to recurrence rate and nerve paraesthesia. There were no recurrence observed in cases treated with 5-FU (n=56), and the incidence of nerve paraesthesia was 20% (none permanent). This systematic review has revealed early encouraging results for 5-FU as an adjunct, however a caution is recommended due to overall low quality of evidence related to individual studies. We present the cumulative evidence on the effectiveness of 5-FU in OKC treatment with discussion on its mechanism of action, safety profile, application protocol, and the implications for clinical practice.     

Keratoameloblastoma: a tumor sui generis or a chimera?

The term keratoameloblastoma has been used to describe a histologically heterogeneous group of ameloblastoma variants which have in common the formation of keratin by the ameloblastomatous epithelium. The English language literature contains reports of only 12 cases of keratoameloblastoma, of which 4 cases exhibited a papilliferous component. We report a unique tumor that we believe falls within the broad histopathologic spectrum of keratoameloblastoma. We review the key clinical and histopathologic features of the previously reported cases of keratoameloblastoma and present an additional case that presented as an expansile, radiolucent lesion with internal opacification between the roots of teeth in the left anterior maxillary alveolar ridge of a 45-year-old white male. There is wide variation in the histopathologic appearance of cases reported under the appellation keratoameloblastoma. Our case exhibited a histopathologic feature shared by only 2 of the previously reported cases, notably islands and anastomosing cords of epithelium forming lamellated, pacinian-like stacks of parakeratin that extruded into the collagenous tumor stroma without eliciting a foreign body response. Due to the small number of reported cases, we are unable to accurately assess whether the biologic behavior of keratoameloblastoma differs from other histologic types of ameloblastoma.