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.     

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.     

Compound composite odontoma with unusual number of denticles – A rare entity

Compound odontoma is stated to be a hamartomatous lesion rather than a true odontogenic tumour. It has an unknown etiology and often suspected when there are retained deciduous teeth in children. Early detection and surgical enucleation of the tumour is recommended to prevent impaction of unerupted teeth. In this index case, multiple denticles or rudimentary teeth, numbering 37 were enucleated from the maxillary anterior region of a 17-year old male, which makes this case unusual. Evidence of concrescence, fusion and dilaceration were observed in the denticles enucleated, the size of which varied from 4 mm to 12.5 mm.     

Imaging angiogenesis: Perspectives and opportunities in tumour research – A method display

The growth of solid tumours necessitates angiogenesis. The aim of this paper is the presentation and evaluation of different ex vivo methods for analysing tumour angiogenesis.Oral squamous cell carcinomas (SCC) were induced in mice by subcutaneous injection of tumour cells in the groin region and processed for histology and microvascular corrosion casting. Vascularization was analysed light microscopically using CD31 immunochemistry. Corrosion casts were analysed by scanning electron microscopy (SEM), micro computed tomography (μCT) and synchrotron radiation-based micro computed tomography (SRμCT).Immunochemistry allows for a simple and authentic detection and stereological quantification of the SCC vascularization. μCT imaging of the corrosion casts gives a high-quality overview over the three-dimensional (3D) microvascular architecture. SEM and SRμCT allow a high-definition display of the vessel morphology, providing magnificent detail recognition down to the capillary level enabling imaging of different forms of tumour angiogenesis, e.g., sprouting and intussusceptive angiogenesis.Immunochemistry and SEM are regarded as suitable for most of the morphometrical and morphological assessments because of the simple procedure and the high explanatory power, especially in combination with each other. High resolution SRμCT helps answering specialized questions, however, requires sophisticated data processing for visualization and is of limited availability.     

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.     

A rare condition of Hand-Schüller-Christian disease

The authors present the clinical case of a 61-year-old patient with Hand-Schüller-Christian disease associated with multisystemic involvement. The onset of such puzzling symptoms and the extremely rarity of this disease in a patient of such advanced age resulted in a delayed diagnosis and subsequently delayed treatment of the patient.     

Volumetric analysis of keratocystic odontogenic tumors and non-neoplastic jaw cysts – Comparison and its clinical relevance

The keratocystic odontogenic tumor (KCOT) is capable of causing vast osseous destruction. Histopathological examination is pivotal for diagnosis. The diagnostic process can sometimes be hindered by tissue inflammation of KCOTs with loss of defining criteria, resulting in misdiagnosis as an odontogenic jaw cyst. We discuss the possible merits of volumetric analysis when facing this particular diagnostic dilemma and for pathophysiological characterization of KCOTs. We included 114 patients, of whom 27 were histopathologically diagnosed with a KCOT and 87 with dentigerous (n = 41) and periapical cyst (n = 46). Semiautomatic segmentation and radiological analysis of preoperative cone beam computed tomography (CBCT) image data was carried out using ITK-SNAP. The mean volumetric extent of KCOTs is significantly higher compared to non-neoplastic odontogenic jaw cysts (p = 0.001). The mean volume and standard deviation for KCOTs and non-neoplastic odontogenic jaw cysts was 10381 mm³ ± 6410 and 5813 mm³ ± 4425, respectively. Volumetric analysis reveals that KCOTs significantly exceed the mean size of non-neoplastic odontogenic jaw cysts, adding an argument in favor of the neoplastic nature of KCOTs. In the case of difficult histopathological examination, lesions with a size exceeding a value of about 3000 mm³ could be considered for close clinico-radiologic follow-up.     

Osteo-odonto-keratoprosthesis – A maxillofacial perspective

The OOKP (osteo-odonto-keratoprosthesis) is the treatment of choice for conditions like Stevens–Johnson syndrome, ocular cicatricial pemphigoid, trachoma, multiple failed grafts and chemical burns which are not amenable to penetrating keratoplasty. The OOKP is an autograft which replaces the cornea with a polymethacrylate cylinder mounted on a tooth-bone complex. The aim of this paper was to retrospectively analyze the records in 26 patients undergoing OOKP surgery between 2007 and 2011. The paper describes our experience with the procedure, with emphasis on its oral and maxillofacial aspects and management of associated complications. The aetiology of blindness in 23 patients was Stevens–Johnson's syndrome and chemical burns in three. Twenty-two patients had their maxillary canines, two had mandibular canines and two had maxillary first premolars as the choice of donor tooth. An oroantral fistula developed in four patients. One patient needed to undergo a surgical procedure for closure of the same. Roots of adjacent teeth were exposed in 12 patients. Twenty-four patients underwent both stages of the procedure with 19 being visually rehabilitated successfully. There was no improvement in the vision of four patients. One patient was lost to follow-up. Two patients have yet to undergo Stage 2.     

A case of supernumerary tooth in the mandibular anterior region – Report on a rare case of five mandibular incisors

Occurrence of a supernumerary tooth in the mandibular anterior region is uncommon. We report the case of a 7-year-old male patient with five incisors including one impacted tooth in the mandibular anterior region. We extracted one of the four erupted teeth to assure the eruption of the impacted tooth within the dentition. Eleven months after tooth extraction, the incisor erupted within the dentition and the incisors exhibited close to normal arrangement. This case indicates that favorable outcomes can be achieved for cases of supernumerary teeth in the mandibular anterior region by treating in the early mixed dentition period.     

Permanent mandibular incisor with multiple anomalies – Report of a rare clinical case

BackgroundMorphological alterations in tooth structure involving either crown or root are common in the literature. But co-occurrence of multiple anomalies in a permanent mandibular central incisor is extremely rare.Case reportThis paper reports an unusual combination of multiple dental anomalies–talon cusp, dens invaginatus and macrodontia affecting both the crown and root of a permanent mandibular left central incisor of a 12-year old Indian boy. Case management has been described and the implications are discussed.ConclusionDiagnosis and treatment of teeth affected by multiple anomalies is a challenging proposition, requiring careful clinical and radiographic interpretation.     

Mucormycosis associated with juvenile diabetes–A rare case report

Mucormycosis is one of the most rapidly progressing and lethal form of fungal infection in humans which usually begins in the nose and paranasal sinuses. The fungus assaults the arteries leading to thrombosis that subsequently causes necrosis of hard and soft tissues. The purpose of this article is to describe a rare case of maxillary necrosis due to mucormycosis in a 12-year-old diabetic patient and emphasizes early diagnosis and timely management of this potentially fatal fungal infection.     

A rare case of iatrogenic gingival Kaposi’s sarcoma

Kaposi’s sarcoma is an angioproliferative tumour rarely found in the oral cavity. We present the 3rd case of iatrogenic gingival Kaposi’s sarcoma reported in the English-language literature which developed in a young patient 5 years after a renal transplant and discuss their histological features and differential diagnosis.     

Ectodermal dysplasia – A cephalometric appraisal

Ectodermal dysplasia (ED) is a rare genetic disturbance affecting the tissues of ectodermal origin with mutation carried by X chromosome with partial expression in females and major manifestation in male sex. It often presents problems of partial or total anodontia of one or both the series of dentition. Absence of complete dentition is rare.During a time span of 10 years, 4 cases (3 females & 1 male) affected with ectodermal dysplasia have been reported. Female subjects showed varying degree of anodontia while the male suffered from complete absence of both primary and permanent dentition.It is interesting to note a higher ratio of affected females, 3 females against 1 male. Females of course exhibited slight lesser manifestation of ED than observed in male. This is in agreement with phenomena of doses compensation of Lyons Hypothesis.Cephalometric angular and linear measurements revealed that ED subjects exhibit tendency for mild mandibular prognathism in the females. Linear dimension exhibit lesser dimensions with tendency to retruded maxilla and significant reduction in lower facial height due to hypodontia and absence or poor development of alveolar ridges. It is also interesting to note that only reported female members of their families were affected by ED and none of the parents or other members of their families were affected.     

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.