J Bagh College Dentistry Vol. 33(4), December 2021 Odontogenic Cysts and 83 Odontogenic Cysts and Tumors of Maxilla and Maxillary Sinus (A Clinicopathological Analysis) Shahad A. Waheed(1), Taghreed F. Zaidan(2), Bashar H. Abdullah(3) https://doi.org/10.26477/jbcd.v33i4.3018 ABSTRACT Background: Knowledge about the prevalence and distribution of pathologies in a particular location is important when a differential diagnosis is being formulated. The aim of this study was to describe the prevalence and the clinicopathological features of odontogenic cysts and tumors affecting the maxilla and to discuss the unusual presentation of those lesions within the maxillary sinus. Materials and Methods: A multicenter retrospective analysis was performed on pathology archives of patients who were diagnosed with maxillary odontogenic cysts and tumors from 2010 to 2020. Data were collected with respect to age, gender and location. Result: A total of 384 cases was identified, 320 (83.3%) cases were diagnosed as odontogenic cysts and 64 (16.6%) as odontogenic tumors. The mean age was 30.5 years with a standard deviation of 16.2 years. Male patients were more commonly affected (n=220, 57.3%). Radicular cyst was the most common cyst (n=205, 64.1%), while the most common tumor was odontoma (n=14, 21.9%) and dentigerous cyst was the most common lesion to present within the maxillary sinus. Conclusion: This study indicates that there are some geographic similarities and differences in regard to distribution of odontogenic cysts and tumors in the maxilla and it raises awareness of their presentation within the maxillary sinus especially if there is an association with an ectopic or adjacent impacted tooth. Keywords: Odontogenic cysts, odontogenic tumors, maxillary sinus, maxilla. (Received: 2/10/2021, Accepted: 31/10/2021) INTRODUCTION The microscopic features of jaw bones are similar to any other bones in the body. Their uniqueness is derived from the fact that they enclose the odontogenic apparatus, a structure that gives rise to a variety of diseases: developmental, inflammatory and neoplastic.(1) Odontogenic cysts are the most common jaw lesions and can be either inflammatory or developmental in origin.(2) On the other hand, odontogenic tumors (OGTS) are rare, accounting for less than one percent of all oral tumors. These tumors might pose a diagnostic challenge for both clinicians and pathologists due to their rarity and overlapping histopathological features.(3) The anatomic location of the maxillary sinus within the body of maxilla makes it vulnerable to the same conditions that affect maxillary bone. Odontogenic lesions of the maxillary sinus are scarce in literature limited mostly to case reports or series. (4,5,6) Most studies investigated the prevalence and distribution of those lesions in both jaws, no study was found to focus entirely on the maxilla and data. (1) Master Student, Department of Oral Diagnosis, College of Dentistry, University of Baghdad. (2) Professor, Department of Oral Diagnosis, College of Dentistry, University of Baghdad. (3) Professor, Department of Oral Diagnosis, College of Dentistry, University of Baghdad. Corresponding author, Shahadwaheed@yahoo.com MATERIALS AND METHODS Data for this retrospective study were collected from the filing systems and pathology archives of nine histopathology laboratories in Baghdad city during the period from 2010 – 2020. The inclusion criteria were histopathology reports for patients diagnosed with an odontogenic cyst or odontogenic tumor affecting the maxilla or maxillary sinus. Duplicate reports and recurrences of previously diagnosed or treated lesions were excluded. In relation to the anatomic site of the lesions, two main sites were identified (maxilla and maxillary sinus). Further maxillary lesions were divided into three segments based on the clinical and radiographic findings; anterior maxilla extends from right canine to left canine. Posterior maxilla extends from the first premolar to maxillary tuberosity, and the palate. Histological diagnoses for the lesions were classified into categories according to the most recent World Health Organization (WHO) Classification of head and neck tumors 2017.(7) Cysts were classified according to origin into inflammatory and developmental while odontogenic tumors into epithelial tumors, mixed epithelial and mesenchymal tumors, and mesenchymal tumors. OGTS were also divided into two types; benign and malignant tumors. A histopathology examination was performed whenever there was a doubt about the diagnosis using available histologic slides stained with hematoxylin and eosin (H&E) by an oral pathologist (B.A). The raw collected data were organized and subdivided into categories using Microsoft Excel 2010 sheets. No https://doi.org/10.26477/jbcd.v33i4.3018 J Bagh College Dentistry Vol. 33(4), December 2021 Odontogenic Cysts and 83 formal statistical tests were done; only descriptive analysis was performed using Statistical Package for Social Sciences (SPSS) version 23. RESULTS A total of 7384 histopathology reports of oral and maxillofacial lesions was found, 1064 (14.4) of cases were identified in the maxilla, of those 384 (36.09%) cases in the odontogenic cysts and tumors group; 320 (30.07%) odontogenic cysts and 64 (6.01%) odontogenic tumors. The mean age was 30.5 years with a SD of 16.2 years. Male patients were affected more (n=220, 57.3%) than females (n=164, 42.7%). Odontogenic cysts: 338 cases were identified in the cysts category; 18 (1.6%) cases were non-odontogenic cysts and 320 (29.5%) odontogenic cysts. Males were affected more (n=187, 58.4%) than females. The mean age was 30.48 years. Most cysts were inflammatory in origin (n=211, 65.9%), while developmental cysts represent (n=106, 33.12%) and 3 cases were not otherwise specified (0.9%). The most common diagnosis was radicular cyst (n=205) followed by dentigerous cyst and keratocyst. Table 1 demonstrates the frequency and distribution of different odontogenic cysts according to gender and age. Table 1: The frequency and distribution of odontogenic cysts according to gender and age. Diagnosis Frequency Gender Age (years) N % M F M:F Mean SD Min Max Radicular cyst 205 64.1 113 92 1.2 32.3 14.65 8 80 Dentigerous cyst 49 15.3 38 11 3.45 23 17.54 6 61 Keratocyst 45 14.1 26 19 1.36 29.08 15.48 10 85 Calcifying odontogenic cyst 8 2.5 4 4 1 39.37 23.07 9 64 Residual cyst 6 1.9 2 4 0.5 43.66 15.27 27 65 Odontogenic cyst not otherwise specified 3 0.9 1 2 0.5 24.66 5.507 19 30 Eruption cyst 1 0.3 1 0 3 . 3 3 Gingival cyst of newborn 1 0.3 0 1 1 week . 1 week 1 wee k Lateral periodontal cyst 1 0.3 1 0 19 . 19 19 Orthokeratinized cyst 1 0.3 1 0 15 . 15 15 Total 320 100 187 133 1.4 30.48 15.97 1 week 85 Odontogenic tumors: Males were affected slightly more (n= 33, 51.6%) than females. The mean age was 31 years. Most tumors were of epithelial origin (n=25, 39.1%) while mesenchymal origin represent (n=23, 35.9%) and mixed origin was (n=16, 25%). Almost, all were benign tumors (n=62, 96.9%) except for two malignant cases (n=2, 3.1%). The most common diagnosis was Odontoma (n=14) followed by both ameloblastoma and odontogenic myxoma (n=12, 18.8%), as shown in (Table 2). Site: The precise site was reported in 196 cases with most lesions affecting the anterior maxilla (n=122, 62.2%), while posterior maxilla was (n=38, 19.38%), palate (n=16, 8.16%). Few cases were reported in maxillary sinus (n=20, 10.2%) (n=8 dentigerous cysts, n=6 radicular cysts, n=2 keratocyst, n=1 Orthokeratinized cyst, n=1 Adenomatoid odontogenic tumor, and n=2 myxoma). J Bagh College Dentistry Vol. 33(4), December 2021 Odontogenic Cysts and 04 Table 2: The frequency and distribution of odontogenic tumors according to gender and age Diagnosis Frequency Gender Age (years) N % M F M:F Mean SD Min Max Odontoma 14 21.9 5 9 0.55 19.4 11.58 8 45 Ameloblastoma 12 18.8 10 2 5 51.83 17.19 30 85 Myxoma 12 18.8 5 7 0.7 28.25 11.09 15 45 Odontogenic fibroma 10 15.6 5 5 1 34.5 13.8 14 54 Pindborg tumor 5 7.8 2 3 0.66 24.2 11.4 13 43 Adenomatoid odontogenic tumor 4 6.3 2 2 1 19.25 5.67 13 25 Unicystic ameloblastoma 2 3.1 0 2 21.5 4.9 18 25 Ameloblastic fibroma 1 1.6 0 1 12 . 12 12 Cementoblastoma 1 1.6 1 0 25 . 25 25 Ghost cell carcinoma 1 1.6 1 0 48 . 48 48 Malignant ameloblastoma 1 1.6 1 0 74 . 74 74 Primordial odontogenic tumor 1 1.6 1 0 14 . 14 14 Total 64 100 33 31 1.06 31.1 17.7 8 85 DISCUSSION Many previous studies analyzed those lesions in both jaws; however, no study focus entirely on the maxilla; because of that to facilitate comparison, some of these studies were reviewed and information regarding maxillary odontogenic lesions was extracted and displayed in (Table 3) and (Table 4) In regard to odontogenic cysts, most of the cysts were of inflammatory origin and radicular cyst was the most common diagnosis which is in accordance with all previous studies in (Table 3).(8, 9,10,11,12) The second most common odontogenic cyst was dentigerous cyst (15.3%) which is similar to other studies.(8, 9,10,12). But it disagrees with Del Corso et al.(11) These cysts are developed in association with unerupted teeth mostly maxillary canine and third molars with predilection for patients in the second decade of life.(9) Odontogenic keratocyst was the third most common cyst in the maxilla which is similar with Izgi et al., and Kambalimath et al studies.(8,10) This study followed the 2017 WHO classification that reclassified keratocyst from benign tumor to a cyst; in contrast to some previous published studies that followed the old classification.(9,14) This study showed a close prevalence between dentigerous cyst and keratocyst (15.3%, 14.1%) respectively. This could be explained by the fact that most dentigerous cysts are small, symptomless, discovered accidently on radiographs and clinicians may not request a histopathology examination relying only on clinical diagnosis. Keratocyst usually grow to larger sizes, produce more obvious clinical symptoms and require further surgical intervention. Regardless the size or appearance, any cystic lesions of the jaw should raise the suspicion of more aggressive odontogenic lesion such as keratocyst, ameloblastoma, pindborg tumor especially due to the fact that many of them can be associated with impacted teeth and resemble the radiographic appearance of dentigerous cyst.(13) J Bagh College Dentistry Vol. 33(4), December 2021 Odontogenic Cysts and 04 Table 3: The characteristics of maxillary odontogenic cysts in comparison studies Study (author, year) Country Number of cases in the maxilla The most common cysts (N) Time period (years) (Izgi et al., 2021).(8) Turkey 165 Radicular cyst (95) Dentigerous cyst (22) Keratocyst (13) (2008 – 2018) (Villasis-Sarmiento et al., 2017).(9) Mexico 337 Radicular cyst (215) Dentigerous cyst (110) Residual cyst (5) (2000 – 2013) (Kambalimath et al., 2014).(10) India 76 Radicular cyst (57) Dentigerous cyst (7) Keratocyst (3) (2001 – 2011) (Del Corso et al., 2014).(11) Italia 374 Radicular cyst (205) Keratocyst (48) Dentigerous cyst (21) (1992 – 2012) (Bataineh et al., 2004).(12) Jordan 313 Radicular cyst (149) Dentigerous cyst (67) Residual cyst (59) LPC (34) (1989 – 2001) With regard to odontogenic tumors, almost all tumors were benign with only two malignant cases such finding is in accordance with all studies in (table 2).(14,15,16,17) Most tumors were of epithelial origin which is similar with Nalabolu et al.(14) The most common tumor in this study was odontoma that is similar to previous studies.(15,16,17) Odontoma represents a hamartous lesion rather than a true neoplasm and is believed to be the most common odontogenic tumor like lesion; however, it is usually asymptomatic and diagnosed accidentally on radiograph. This could be the reason for the small number of cases in this study since patients do not seek treatment until obvious symptoms appear.(14) Geographic, genetic and environmental factors can also affect the prevalence of odontomes.(14) Similar to other studies, this lesion showed a high prevalence in the second decade of life.(14,16) Ameloblastoma was the second most common tumor which was in agreement with Taghavi et al.(17) and with other studies. (15,16) If keratocyst was excluded, a male predilection was shown with male to female ratio of 5:1 which disagrees with Zwahlen and Grätz literature review,(18) that reported no gender predilection. Although maxillary ameloblastomas are rare compared to those of the mandible; they still ranked high among OGTS in this study. This tumor is aggressive, usually showing extensive extension into the adjacent structures such as nasal cavity and maxillary sinus,(19) and can clinically mimic a sinonasal malignancy. Ameloblastoma can arise primary from the surface epithelium of the maxillary sinus; however, such a diagnosis is rare and can’t be made without excluding an extension from the surrounding maxillary bone first.(20) Odontogenic myxoma is a benign mesenchymal tumor. It is reported as the third most common odontogenic neoplasm of jaw after odontoma and ameloblastoma.(17) In this study, it showed a similar prevalence to ameloblastoma (18.8%) and two cases were reported initially as sinus lesions. This lesion usually arises within the maxillary bone and invades the adjacent sinus; however sinonasal counterparts have been rarely reported in the literature.(21) There are different theories regarding the etiology of this lesion in sinus. Myxomas may arise from modified fibroblasts associated with tooth germ in which these altered cells can hyper secrete mucin.(22) The association between myxoma and impacted teeth has provided support for this theory. However, evidence exists that argues against this odontogenic theory a study by Slootweg and Wittkampf.(23) demonstrated that the extracellular matrix of myxomas differs histologically from the extracellular matrix of dental and periodontal tissues. Also, the presence of reported cases of myxomas in remote sites from odontogenic tissues such as sphenoid sinus.(24) This study also reported other rare lesions in less numbers such as calcifying odontogenic cyst (2.5%), Pindborg tumor (7.8%), unicystic ameloblastoma (3.1%), ameloblastic fibroma (1.6%), cementoblastoma (1.6%) and one case of the newly described entity primordial odontogenic tumor that J Bagh College Dentistry Vol. 33(4), December 2021 Odontogenic Cysts and 04 was published previously by the author (B.A.) as the first Iraqi case report.(25) The anterior maxilla was more commonly affected in both cysts and tumors; a finding that is similar with Izgi et al.(8) Table 4: The characteristics of maxillary odontogenic tumors in comparison studies Study (author, year) Country Number of cases in the maxilla The most common tumors (N) Time period (years) (Nalabolu et al., 2017).(14) India 45 Keratocyst (17) Ameloblastoma (16) Odontoma (6) Adenomatoid odontogenic tumor (6) (2002 – 2014) (AlSheddi et al., 2015).(15) Saudi Arabia 52 Odontoma (15) Keratocyst (14) Ameloblastoma (6) (1984 – 2010) (Avelar et al., 2008).(16) Brazil 78 odontoma (31) keratocyst (17) Ameloblastoma (9) myxoma (8) (1992 – 2007) (Taghavi et al., 2013).(17) Iran 50 Odontoma (16) Ameloblastoma (13) Myxoma (11) (2000 – 2010) Maxillary sinus is vulnerable to diseases of odontogenic origin due to its proximity with developing teeth and root apices. Diagnosis of such lesions in this location is challenging as routine radiographs do not offer characteristic features and show overlaps of various adjacent structures.(26) Most odontogenic cysts and tumors in this location are associated with an ectopic tooth inside the sinus with the commonest being dentigerous cyst.(27,28) which is similar to this study findings. Many theories exist regard the etiology of those ectopic teeth including trauma, developmental and pathologic conditions. The most likely scenario is the presence of impacted tooth (mostly canine or molars) in close anatomic relation to the sinus wall and as the cyst grows and enlarges it displacing the tooth inside the sinus space.(4) Other odontogenic cysts had also been reported infrequently to involve the maxillary sinus. Radicular cyst can grow to large sizes, breach the sinus wall and occupy the entire sinus space.(6) Keratocysts can also involve the maxillary sinus with a controversy regarding its origin; it might arise from the entrapment of dental lamina within the sinus during normal development due to the close anatomic relation,(29) or from normal expansion of an adjacent intraosseous cyst, or in relation to an ectopic tooth inside the sinus.(5) CONCLUSION There are some geographic similarities and differences with regard to the prevalence and distribution of odontogenic cysts and tumors of maxilla. The presence of these lesions within the maxillary sinus is uncommon and different theories exist in the literature regarding their origin; nevertheless, they should be included in the differential diagnosis of sinus lesions especially if there was an association with an ectopic or adjacent impacted tooth. Conflict of interest: None. REFERENCES 1. 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Oral Surg Oral Med Oral Pathol. 1987;64:648-51. المستخلص: الخلفية: المعرفة حول انتشار وتوزيع األمراض في موقع معين أمر مهم عند صياغة التشخيص التفريقي. كان الهدف من هذه الدراسة هو وصف األنفية غير المعتاد لتلك اآلفات داخل الجيوب ظهورالسنية التي تصيب الفك العلوي ومناقشة الاالنتشار والسمات اإلكلينيكية لألكياس واألورام للمرضى الذين تم تشخيصهم باألكياس واألورام التشخيص النسيجي تقاريرمتعدد المراكز على رجعيالمواد والطرق: تم إجراء تحليل .الفكية .. تم جمع البيانات فيما يتعلق بالعمر والجنس والموقع0202إلى عام 0202السنية في الفك العلوي من عام انحراف معياري سنة مع 42.3العمر ( أورام سنية. كان متوسط ٪04.4) 43( حالة كيسات سنية و ٪84.4) 402 حالة، 483النتيجة: تم تحديد هو الكيس األكثر شيوًعا Radicular cyst كيس الجذري(. كان ال٪4..3، 002) كانوا اكثر عرضة لالصابة سنة. المرضى الذكور 04.0 ( وكان كيس األسنان ٪00.2، 03)العدد = odontoma ( ، بينما كان الورم األكثر شيوًعا هو الورم السني٪43.0، 023)العدد = Dentigerous cystهو اآلفة األكثر شيوًعا الموجودة داخل الجيب الفكي. الفك العلوي واألورام السنية في كياسالدراسة إلى أن هناك بعض أوجه التشابه واالختالف الجغرافي فيما يتعلق بتوزيع اال: تشير هذه االستنتاج .مطمور وزيادة الوعي بمظهرها داخل الجيوب األنفية الفكية خاصةً إذا كان هناك ارتباط مع سن مجاور Articles Published by Journal of Baghdad College of Dentistry is licensed under a Creative Commons Attribution 4.0 International License.