Clinical and histopathological evaluation of odontogenic cysts

Vol. 74 | No. 6/1 | Jun 2018 DOI: 10.21506/j.ponte.2018.6.5

International Journal of Sciences and Research

Clinical and histopathological evaluation of odontogenic cysts according to World Health Organization new classification of odontogenic cysts: A preliminary study Onur ŞAHİN1, Onur ODABAŞI2 1

Department of Oral and Maxillofacial Surgery, Faculty of Dentistry, İzmir Katip Çelebi Universty, İzmir, Turkey

2

Department of Oral and Maxillofacial Surgery, Mamak Dental Health Centre, Ankara, Turkey

Corresponding Author: Onur Şahin Aydınlıkevler Mah. 6782 Sok. No: 48 35640 Çiğli/ İzmir/ Türkiye, Phone number: +905054410192, Fax: +90 (232) 325 25 35 e-mail: [email protected] Abstract Background: Having knowledge about the frequency and distribution of cysts helps to know the possible diagnosis and complications of cysts and to plan appropriate treatment. There are many studies on the prevalence of odontogenic cysts in literature. However, these studies are based on the WHO classifications of 1992 and 2005, and there is no study using the latest classification updated in 2017. In this study, the latest classification scheme of WHO in 2017 is used.

59



Methodology: Data were collected from the medical records of the 462 odontogenic cyst patients regarding age, gender, follow-up duration, systemic conditions, localization of the cysts, examination findings before the operation, treatment methods applied, provisional diagnosis and pathology report. Cystic lesions were classified according to the new WHO classification in 2017. Results: Pathology reports showed 246 patients had (53.2%) radicular cyst, 3 patients (0.6%) had inflammatory collateral cyst, 78 patients (16.8%) had dentigerous cyst, 51 patients (11.1%) had odontogenic keratocyst, 12 patients (2%) had lateral peridontal cyst, 15 patients (3.2%) had gingival cyst, 18 patients (3.8%) had glandular odontogenic cyst, 9 patients (1.9%) had calcifying odontogenic cyst , 6 patients (1.2%) had orthokeratinized odontogenic cyst and 24 patients (5.2%) had nasopalatine duct cyst. Conclusion: Radicular cyst,dentigerous cyst and odontogenic keratocyst are the most prevalent odontogenic cyst in this study. The future studies might include more participants to evaluate for odontogenic cysts prevalence, odontogenic and non-odontogenic tumours, malign tumours, and precancerous lesions in oral cavity using the WHO classification scheme updated in 2017. Keywords: Odontogenic cyst, Odontogenic keratocyst, Update, WHO classification

Introduction Pathological formations, surrounded by epithelium and containing liquid or semi-liquid material, are called cysts. Cysts arising from the epithelium of the tooth structures are called odontogenic cysts (OC).1 Cysts are most commonly seen at jaw in the body as the epithelial

60



reminants are more at jaw than the rest of the body.2 Odontogenic cysts usually show similar clinical and radiological features, so a false clinical diagnosis is possible.3 Thus, the tissues obtained by surgical excision must be properly examined histopathologically, and diagnosed correctly for the proper treatment.4

Having knowledge about the frequency and distribution of cysts helps to know the possible diagnosis and complications of cysts and to plan appropriate treatment.5 The classifications published by World Health Organisation (WHO) in 1992 and 2005 were used in the studies done on odontogenic cysts so far in literature.6,7 The classification of odontogenic cysts changed after an update by WHO earlier in 2017.8 With the latest update, odontogenic cysts are divided into 2 groups as inflammatory odontogenic cysts, and developmental odontogenic and non-odontogenic cysts. Odontogenic cysts of inflammatory origin are classified as radicular and inflammatory collateral cysts. Developmental odontogenic and non-odontogenic cysts are classified as dentigerous cysts, odontogenic keratocysts, lateral peridontal cysts and bothroid odontogenic cysts, gingival cysts, glandular odontogenic cysts, calcifying odontogenic cysts, orthokeratinized odontogenic cysts and nasopalatine duct cysts. The two most important changes in the new classification are the involvement of keratocystic odontogenic tumor and calcifying cystic odontogenic tumor considered as tumor in the classification in 2005 to the group of cysts as odontogenic keratocyst (OKC) and calcifying odontogenic cyst (COC) in the 2017 classification.9 (Table 1) Orthokeratinized odontogenic cysts (OOC) are also included in the classification. OOC is a developmental odontogenic cyst which has a orthokeratinized squamous epithelium lining. It was defined as a type of odontogenic keratocyst in the previous classifications.It has been evaluated as a separate type of cyst for the first time in 2017 classification. OOCs are different from OKCs both clinically 61



and histopathologically. OOCs are not related to any syndrome and unlike OKCs, they don’t have high relapse rates and aggressive clinical features. Updates on glandular odontogenic cysts (GOC) are also available in the new classification. Ten different histopathological features have been described and seven diagnostic criterias have been suggested regarding GOC. No important changes have been made in other odontogenic cysts. Lateral peridontal cyst was first included in the classification in 1992. It is included in developmental cysts in the new classification with its multilocular variant bothroid odontogenic cysts. Gingival cysts were classified as gingival cysts of adult and newborn in the classification of 1992. They are only mentioned as gingival cysts in the new classification. A separate cyst group in the 1992 classification, eruption cyst, is defined as a variant of dentigerous cyst in the new classification.10 There has been changes in inflammatory cysts in the new classification. Inflammatory cysts were grouped as radicular and paradental cysts in 1992. However, in the new classification inflammatory cysts are grouped as radicular and inflammatory collateral cysts. Residual and lateral radicular cysts are classified as a variant of radicular cysts. Inflammatory cysts such as paradental cysts and mandibular buccal bifurcation cysts are grouped as inflammatory collateral cysts for the first time in the new classification.9,10

62



Table 1: 2017 WHO classification of odontogenic cysts8

Odontogenic Cysts Odontogenic cysts of inflammatory origin Radicular cyst Inflammatory collateral cyst Odontogenic and non-odontogenic developmental cysts Dentigerous cyst Odontogenic keratocyst Lateral periodontal cyst and botryoid odontogenic cyst Gingival cysts Glandular odontogenic cyst Calcifying odontogenic cyst Orthokeratinized odontogenic cyst Nasopalatine duct cyst

In the literature, there are many studies on prevalence of odontogenic cysts. However, these studies are based on the WHO classifications in 1992 and 2005. No studies evaluating odontogenic cysts according to the classification in 2017 could be found in literature. For this purpose, 462 jaw cyst cases were retrospectively grouped according to the latest update of WHO and evaluated based on age, gender, localisation, treatment method, the compatibility of provisional clinical diagnosis and histopathologic examination, and histopathologic features to contribute to the literature.

63



Methodology In this study, cases with odontogenic cysts referred to our clinics between 2013 January-2018 January and surgically treated were retrospectively evaluated considering their histopathologic features and clinical and radiological findings. The ethical committee of our university approved this retrospective study. The age, gender, follow-up duration, systemic conditions, localization of the cysts, examination findings before the operation, treatment methods, provisional diagnosis, pathology report, development of complications after the operation and the recurrence situations of the patients whose clinical and radiological examinations were done were recorded. Cystic lesions were classified as radicular cyst, inflammatory collateral cyst, dentigerous cyst, odontogenic keratocyst, lateral peridontal cyst, gingival cyst, glandular odontogenic cyst, calcific odontogenic cyst, ortokeratinised odontogenic cyst and nasopalatine duct cyst according to the new WHO classification in 2017. (Fig. 1-2) The distribution of the cysts according to localisation, age and gender is given in Table 2. Statistical analysis of the data was done by SPSS 21.0 (Statistical Package for the Social Sciences, Chicago, IL, USA) package program. Chi square test was used to examine the possible association between cyst types and age and gender. ( p