Paradental cyst is an inclusion cyst of the junctional/sulcular epithelium of the gingiva: histopathologic and immunohistochemical confirmation for its pathogenesis

Current Perspectives on Paradental Cyst: A Literature Review

Paradental cyst (PC) is an uncommon type of odontogenic cyst of inflammatory origin, which develops near the cervical margin of the outside of the root of a vital tooth. The category of paradental cyst includes the buccal bifurcation cyst, which is found in the buccal area adjacent to the mandibular first or second molars in children. A conclusive diagnosis of a PC needs to correlate the surgical, radiographic, and histologic findings. When strict diagnosis is neglected, they can be easily misdiagnosed and mistreated. PCs associated with mandibular first and second molars and those associated with the mandibular third molar may have slightly different clinical manifestations but have almost completely different treatment principles due to the distinction in location. For the third molars, removal of both the tooth and the cyst is preferred. However, when the first or second molars are affected, it may be advisable to perform enucleation of the lesion while preserving the associated tooth. There are also more conservative methods to retain vital permanent teeth within the mandibular arch. Additionally, the cyst wall primarily consisted of granulation tissue firmly attached to the periodontal ligament space. The exact origin of these cysts was a subject of ongoing debate, but they were believed to primarily arise from either the reduced enamel epithelium or the inflammatory proliferation of junctional/sulcular epithelium, which originate from the superficial mucosa during tooth eruption. The aim of the present review was to update information on clinical manifestations, diagnosis and treatment strategies of cysts and discuss their pathogenic mechanisms. Raising familiarity with the distinctive features is beneficial for accurately diagnosing these lesions and effectively caring for the patients.

Critical assessment of the latest classification of jaw cysts proposed by the World Health Organization (2017)

Background

The fourth edition of the World Health Organization Classification of Head and Neck Tumors was published in January 2017, and includes a classification of odontogenic tumors and odontogenic cysts. The present review assesses the changes made in this new classification in relation to odontogenic and non-odontogenic jaw cysts.

Material and Methods

An electronic search was conducted in the Cochrane Library, PubMed-MEDLINE and Scopus databases using the search terms: “odontogenic cyst” “WHO classification” “update”. Studies written in English and published between January 2005 and April 2020 with a high level of scientific evidence were included, while studies not published in English, epidemiological studies, and studies with a low level of scientific evidence were excluded.

Results

The initial search identified 311 articles, and after the deletion of duplicates, 7 studies were selected for full-text assessment. After excluding two studies that failed to provide relevant information and had a low level of scientific evidence, 5 articles were finally included and stratified according to their level of scientific evidence based on the SORT (Strength of Recommendation Taxonomy) criteria.

Conclusions

The incorporation of odontogenic and non-odontogenic cysts to the head and neck tumors classification underscores the recognition of the WHO of these important disorders of the jaws. Based on the current evidence, there is controversy as to whether odontogenic keratocysts should be regarded as cystic lesions or as neoplasms, though there is no such controversy in relation to calcifying odontogenic cysts. On the other hand, orthokeratinized odontogenic cysts have been included in the classification as a single entity differentiated from odontogenic keratocysts, while residual cysts have been removed from the classification.

Key words:Odontogenic cyst, WHO classification, pseudocyst.

The canine furcation cyst, a newly defined odontogenic cyst in dogs: 20 cases (2013-2017)

OBJECTIVE

To characterize clinical, radiographic, and histologic features of canine furcation cysts (CFCs) in dogs and to propose possible mechanisms of CFC development.

ANIMALS

20 client-owned dogs with CFCs biopsied between January 1, 2013, and December 31, 2017.

PROCEDURES

Medical records of the Center for Comparative Oral and Maxillofacial Pathology at the University of Wisconsin-Madison were retrospectively searched to identify records of dogs that had surgical biopsy specimens of mandibular or maxillary cavitary lesions diagnosed as odontogenic cysts and that met additional inclusion criteria. Biopsy sample submission records, medical records, clinical and radiographic images, and histologic samples were reviewed. Clinical, radiographic, and histologic features were evaluated.

RESULTS

Mean body weight and age of affected dogs were 23.5 kg (51.7 lb) and 8.2 years, respectively. All 20 dogs had a unilateral cyst, with the right (n = 13) or left (7) maxillary fourth premolar tooth affected and viable in all dogs. A predominant clinical sign was a fluctuant swelling of the buccal gingiva and mucosa overlying the CFC, and enucleation of the cyst lining, with or without extraction of the affected tooth, resolved the lesion in most dogs.

CONCLUSIONS AND CLINICAL RELEVANCE

Our findings indicated that CFC is an odontogenic cyst of uncertain etiopathogenesis and that complete evaluation of the clinical, radiographic, and histologic features of the lesion in affected patients is necessary to distinguish a CFC from other odontogenic cysts and tumors in dogs. Defining CFCs in terms of characteristic features permits accurate diagnosis and appropriate treatment of these previously unclassifiable odontogenic cysts in dogs.

World Health Organization Classification of Odontogenic Tumors and Imaging Approach of Jaw Lesions

Tumors of the jaws represent a heterogeneous group of lesions that are classified histologically in the World Health Organization Classification of Odontogenic Tumors (2017). This article provides an update of the current nomenclature. The main role of imaging is to describe the precise location and extent of these lesions. Although characterization of imaging is often difficult due to overlapping characteristics, imaging is helpful to define which lesions should be referred for histologic examination and subsequent treatment planning. Location and density are the cardinal criteria for potential characterization on imaging. Radiologically, lesions may be radiolucent, radiopaque, or of mixed density. Additional criteria include lesion demarcation, morphology, cortical breakthrough, periosteal reaction, and adjacent soft tissue changes. Final lesion characterization is only definitive after interdisciplinary discussion and radiopathologic correlation. Correct diagnosis is obtained by a combination of the patient's age, lesion location, and clinical and radiologic presentation. It is important that all physicians use a uniform nomenclature.

The use of localised CBCT to image inflammatory collateral cysts: a retrospective case series demonstrating clinical and radiographic features

Introduction

Inflammatory collateral cysts are uncommon cysts primarily affecting first permanent molars during their eruption. There are diagnostic challenges that can be overcome with CBCT imaging. However, given the paediatric age group for this condition, there are patient cooperation and radiation dose factors to consider when justifying the scan. The aim of this case series study is to illustrate the value of CBCT in imaging and diagnosing inflammatory collateral cysts in paediatric patients, to highlight the need for a multidisciplinary approach for this uncommon pathological condition and to review the relevant literature.

Case series description and results

We present three patients aged between 6 and 11 years of age with inflammatory collateral cysts affecting their first or second permanent molars for which CBCT imaging was utilised. All patients underwent cyst enucleation with preservation or extraction of affected teeth under general anaesthesia.

Discussion

Inflammatory collateral cysts are likely to be under reported given their indistinct clinical features and radiological signs. Conventional planar radiographs may not reveal this lesions size and full extent. CBCT overcomes these limitations; however, careful assessment of patient cooperation is needed and a low-dose protocol should be used.

Conclusions

CBCT can provide useful imaging information which is difficult to obtain using conventional radiography, especially in cases where an inflammatory collateral cyst is suspected.