Immunohistochemical Comparison of Ki-67 and MCM-3 in Odontogenic Cysts: An Observational Study.

Odontogenic cysts are a diverse group of pathologic entities with different proliferation potential, leading to variations in their biological behavior. One of the most cited proliferation markers used in diagnostic histopathology is Ki-67. Another group of proteins recently investigated is minichromosome maintenance (MCM-3) and its expression has been evaluated in several odontogenic lesions but the results were controversial. Thus, the present study endeavored to compare the expression of MCM-3 and Ki-67 in odontogenic cysts. Furthermore, a pioneer attempt was made to evaluate the sensitivity of these markers to inflammation. A total of 101 cases (37 dentigerous cysts, 37 odontogenic keratocysts, and 27 radicular cysts) were included. Immunohistochemical expression of Ki-67 and MCM-3 were investigated using a labeling index (LI). In addition, they were scored for inflammation, followed by correlation with both markers. The data obtained were subjected to statistical analysis ( P <0.05). Overall, a higher LI of MCM-3 than Ki-67 was obtained in all study groups along with a positive correlation of Ki-67 LI with inflammation. Thus, MCM-3 proteins proved to be a more accurate means to determine the proliferation potential and were not sensitive to external stimuli like inflammation than conventional markers, such as Ki-67.

The Paradigm of the Inflammatory Radicular Cyst: Biological Aspects to be Considered.

Inflammatory radicular cysts (IRCs) are chronic lesions that follow the development of periapical granulomas (PGs). IRCs result from multiple inflammatory reactions led initially by several pro-inflammatory interleukins and growth factors that provoke the proliferation of epithelial cells derived from epithelial cell rests of Malassez present in the granulomatous tissue, followed by cyst formation and growth processes. Multiple theories have been proposed to help explain the molecular process involved in the development of the IRC from a PG. However, although multiple studies have demonstrated the presence of epithelial cells in most PGs, it is still not fully understood why not all PGs turn into IRCs, even though both are stages of the same inflammatory phenomenon and receive the same antigenic stimulus. Histopathological examination is currently the diagnostic gold standard for differentiating IRCs from PGs. Although multiple studies have evaluated the accuracy of non-invasive or minimally invasive methods in assessing the histopathological nature of the AP before the intervention, these studies' results are still controversial. This narrative review addresses the biological insights into the complex molecular mechanisms of IRC formation and its histopathological features. In addition, the relevant inflammatory molecular mediators for IRC development and the accuracy of non-invasive or minimally invasive diagnostic approaches are summarised. (EEJ-2022-03-041).

Detection of bone marrow edema in differential diagnoses of odontogenic cysts using dual-energy computed tomography.

PURPOSE: In this study, we prospectively investigated the relationship between bone marrow edema (BME) and odontogenic cysts and explored the possibility of using dual-energy computed tomography (DECT) as an auxiliary tool for the diagnosis of odontogenic cysts. METHODS: This cross-sectional study included 73 patients who underwent the DECT scan and surgery for odontogenic cysts or odontogenic tumors. The virtual noncalcium (VNCa) computed tomography (CT) values and CT values were measured at several sites. The predictor variable was diagnosis, and the other variables included age, sex, and sites. The primary outcome was VNCa CT value. Variables were tested using the chi-square test or the Kruskal-Wallis test. The VNCa CT and CT values were tested using the Scheffe test for multiple comparisons. All variables were analyzed as independent variables affecting the VNCa CT values around the lesion in the multiple regression analysis. RESULT: There were 35 men and 38 women. The mean patient age was 50.0 ± 19.5 years (range: 8-86). The VNCa CT values (- 6.2 ± 34.3) around the lesion in patients with RCs were significantly higher than those in patients with dentigerous cysts (- 44.4 ± 28.6) and odontogenic keratocysts (- 67.3 ± 19.5). In multiple regression analysis, the VNCa CT values around the lesion showed a significant positive correlation with histological results (regression coefficient: - 0.605, P < 0.001). CONCLUSION: The presence of BME is associated with radicular cysts, and DECT can be used as an auxiliary tool for radicular cyst diagnosis.

Prevalence of Nonendodontic Diagnoses in Periapical Biopsies: A 6-year Institutional Experience.

INTRODUCTION: The purpose of this study was to identify nonendodontic periapical lesions (NPLs) mimicking endodontic pathosis, which are most frequently encountered by clinicians. METHODS: A retrospective study was conducted on biopsies obtained from 2015-2020 at Texas A&M College of Dentistry's oral pathology laboratory. The online database was screened for cases submitted as suspected endodontic pathology using specific key words. Histologic diagnoses were collected to determine the prevalence of NPLs that were originally thought to be of endodontic origin. The frequency and percentage of endodontic pathology and NPLs were documented. RESULTS: Among 6704 biopsies clinically diagnosed as endodontic lesions, 190 (2.8%) were histopathologically diagnosed as NPLs. The most frequent NPLs were odontogenic keratocytes' (n = 70, 36.8%), cemento-osseous dysplasia (n = 27, 14.2%), and dentigerous cysts (n = 22, 11.6%). Of all NPLs, 3.7% were malignant neoplasms, with the most common diagnosis being squamous cell carcinoma. Of 6514 endodontic histologic diagnoses, the prevalence of periapical granulomas and cysts was 60.2% (n = 3924) and 39.1% (n = 2549), respectively. CONCLUSIONS: Although most endodontic submissions are likely to be histologically diagnosed as periapical granulomas or cysts, the clinician should be aware that a small portion of these lesions may be nonendodontic in origin and possibly neoplastic in nature. Histopathologic evaluation of biopsied specimens is critical to achieve a proper diagnosis to ensure the appropriate management of patients.

Pediatric Odontogenic and Maxillofacial Bone Pathology: A Global Analysis.

BACKGROUND: Although pathology in the maxillary and mandibular bones is rare in young patients, the differential diagnosis is broad. The World Health Organization (WHO) updated its classification of maxillofacial bone pathology in 2017. Using these updated guidelines, a systematic review of common maxillofacial bone lesions in the pediatric population was performed. METHODS: A PubMed search was conducted capturing English language articles from inception to July 2020. Thirty-one articles were identified that described the frequency of maxillofacial bone pathology. Data were extracted and organized using the WHO 2017 classification of odontogenic and maxillofacial bone tumors. Prevalence data were analyzed among diagnostic categories and geographical regions. The SAS version 9.4 was used to complete statistical analyses. RESULTS: The articles included patients from birth to a maximum age of 14 to 19 years. The most common odontogenic cysts included radicular cyst (42.7%) and dentigerous cyst (39.0%) followed by odontogenic keratocyst (15.0%). Among odontogenic bone tumors, odontoma (49.3%) was most common followed by ameloblastoma (29.1%). The most common nonodontogenic bone tumor was fibrous dysplasia (42.4%), and the most common malignant bone tumor was osteosarcoma (75.0%). Significant variations were found by geographic region, with dentigerous cyst more common than radicular cyst, and ameloblastoma more common than odontoma in African and Asian countries (P < 0.0001). CONCLUSIONS: This systematic review uses the WHO 2017 guidelines to classify common odontogenic and nonodontogenic maxillofacial bone lesions around the world. Pathogenesis, presentation, and available treatment options for the most common maxillofacial bone lesions are reviewed.

Tratamento cirúrgico conservador de cisto radicular de grande extensão: relato de caso com acompanhamento / Conservative surgical treatment of large extension radicular cyst: case report with follow-up

Introdução: os cistos radiculares são as lesões císticas mais comuns nos maxilares. Eles surgem dos Restos Epiteliais de Malassez, presos no ligamento periodontal e podem ser ativados por um processo inflamatório na região pulpar. Geralmente são descobertos em exames radiográficos de rotina, apresentando-se como uma imagem radiolúcida, bem delimitada, envolvendo o periápice de um ou mais dentes. Objetivo: apresentar o tratamento de um extenso cisto radicular, em região de maxila, com acompanhamento de 18 meses. Relato do caso: Paciente do sexo feminino, 49 anos, foi encaminhada para avaliação e tratamento na Clínica Odontológica da Faculdade Sete Lagoas (FACSETE), apresentando lesão extensa em região maxilar anterior direita ao exame radiográfico. Ao exame clínico, observou-se leve assimetria facial e ausência de sintomas dolorosos. Tomografia computadorizada, punção aspirativa e biópsia incisional foram utilizadas para se chegar ao diagnóstico compatível com cisto radicular. Optou-se por uma técnica conservadora, em que foi realizada a descompressão da lesão. Após 05 meses de tratamento, um novo procedimento cirúrgico foi realizado para enuclear o restante da patologia. Conclusão: a descompressão, com utilização de cânula, é um tratamento auxiliar fácil, conservador, eficaz e reduz a morbidade causada por diferentes cistos odontogênicos(AU)

Introduction: root cysts are the most common cystic lesions in the jaw. They arise from the Epithelial Remains of Malassez, trapped in the periodontal ligament and can be activated by an inflammatory process in the pulp region. They are usually discovered in routine radiographic examinations, presenting as a well-defined radiolucent image involving the periapex of one or more teeth. Objective: to present the treatment of an extensive root cyst, in the maxillary region, with a follow-up of 18 months. Case report: A 49-year-old female patient was referred for evaluation and treatment at the Dental Clinic of Faculdade Sete Lagoas (FACSETE), with an extensive lesion in the right anterior maxillary region on radiographic examination. On clinical examination, mild facial asymmetry and absence of painful symptoms were observed. Computed tomography, aspiration puncture and incisional biopsy were used to reach a diagnosis compatible with radicular cyst. We opted for a conservative technique, in which the lesion was decompressed. After 05 months of treatment, a new surgical procedure was performed to enucleate the rest of the pathology. Conclusion: decompression, using a cannula, is an easy, conservative, effective auxiliary treatment and reduces the morbidity caused by different odontogenic cysts.

Abordagem cirúrgica de cisto periapical infectado em região maxilar: relato de caso / Surgical approach of infected periapical cystin maxillary region: case report

Cistos Periapicais são proliferações dos restos epiteliais de Malassez em decorrência do processo desenvolvimento ou inflamatório devido necrose pulpar. Apresenta-se no início de forma assintomática, e dependendo da sua evolução pode levar a expansão da corticais e reabsorção óssea. Ao exame de imagem se apresentam como uma área radiotransparente bem delimitada, circunscrita por halo radiopaco geralmente associado a região apical de uma ou mais unidades dentárias. O objetivo desse trabalho é relatar abordagem cirúrgica de enucleação e curetagem de um cisto periapical em região maxilar(AU)

Periapical cysts are proliferations of the epithelial remains of Malassez due to the development or inflammatory process due to pulp necrosis. It presents at the beginning asymptomatic, and depending on its evolution may lead to cortical expansion and bone resorption. Imaging studies present as a well-defined radiotransparent area, circumscribed by a radiopaque halo generally associated with the apical region of one or more dental units. The objective of this study is to report a surgical approach of enucleation and curettage of a periapical cyst in the maxillary region(AU)

Accuracy for diagnosis of periapical cystic lesions.

Clinical differentiation between cystic lesions of endodontic and non-endodontic origin is of importance because correct diagnosis may affect treatment decision making. Most radicular cysts are treated with conservative approaches and, therefore, are not surgically removed. The objective of this study was to determine the accuracy of clinical diagnosis of periapical lesions as compared to the histological findings, and to evaluate various associated factors. All biopsy specimens submitted for histological evaluation from 2002 to 2009 were assessed. Only cases of periapical lesions with complete patient data and clinical diagnosis were included. Sensitivity, specificity and accuracy of the clinical diagnosis were calculated and various patient-related factors were evaluated. Of the 4,908 cases, 183 met inclusion criteria. Histologically, there were 171 lesions of radicular cysts and 12 cases of non-endodontic cysts, including OKC and Incisive Canal Cyst. The diagnostic accuracy for clinical diagnosis for radicular cysts was 91.84% and 91.84% for non-endodontic cysts. There was a high accuracy of clinical differentiation between cystic lesions of endodontic and non-endodontic origin. However, some non-endodontic lesions may be incorrectly diagnosed clinically as lesions of endodontic origin. Histological evaluation may be necessary for the correct diagnosis. Further clinical studies are needed to evaluate clinical examination and histological diagnosis of periapical lesions.

Quantitative Analysis of CCL5 and ep300 in Periapical Inflammatory Lesions.

OBJECTIVES: In silico bioinformatical analysis suggested that the expression of two genes, CCL5 (C-C Motif Chemokine Receptor 5) and ep300 (Histone acetyltransferase p300), could be used as potential new biomarkers in differentiation between periapical granulomas and radicular cysts. Thus, we hypothesized that gene expression of CCL5 and ep300 in periapical lesions would classify the lesions as either granuloma or cyst. MATERIALS: Patient samples (n=122) included 46 periapical granulomas, 38 radicular cysts and 38 healthy gingival samples as controls. Real-time PCR analysis of CCL5 and ep300 transcripts was compared to SDHA (Succinate dehydrogenase complex, subunit A) as the reference. Clinical parameters (e.g., intensity of inflammation and lesion size) were measured and correlated with CCL5 and ep300 expression. ROC (Receiver operating characteristic) and logistic regression analyses were used to establish the diagnostic character of ΔCt values. RESULTS: Granulomas and radicular cysts had significantly higher expression of CCL5 and ep300 compared to controls (P<0.05). However, no differences were observed when comparing granulomas and radicular cysts. ROC analyses showed that CCL5 and ep300 have good diagnostic accuracy, but low accuracy for distinguishing between the lesions. CONCLUSIONS: This study confirmed that expression of CCL5 and ep300 is relevant for the pathogenesis of periapical inflammatory lesions but cannot be used as a distinctive marker between these lesions.

[Odontogenic tumors and odontogenic cysts: a clinical and pathological analysis of 4 181 cases].

Objective: To investigate the incidence and constituent ratio of odontogenic tumors or odontogenic cysts in School and Hospital of Stomatology, Jilin University and to provide the reference for the clinical treatment. Methods: According to the WHO 2017 histological classification criteria, the pathological data of 4181 patients diagnosed as odontogenic tumors or odontogenic cysts in the Department of Pathology, Jilin University Stomatological Hospital from January 1961 to December 2017 were collected. Statistical analysis of the pathological types, gender, age and location of various tumors and cysts was conducted. Results: Of 4 181 cases, 1 055 were tumors and 3 126 were cysts. Among odontogenic tumors, benign tumors accounted for 96.11% (1 014/1 055), and malignant tumors accounted for 3.89% (41/1 055). The most common pathological type of odontogenic tumors was ameloblastoma [53.27% (562/1 055)], followed by cemento-ossifying fibroma [21.23% (224/1 055)] and odontoma [12.99% (137/1 055)]. The male-female ratio was 1∶1.04. The high-risk ages were 10-39. Maxilla-mandible ratio was 1∶2.85.As for cysts, radicular cysts [50.45% (1 577/3 126)] was the most common pathological type, followed by odontogenic keratocyst [25.59% (800/3 126)] and dentigerous cysts [21.56% (674/3 126)]. The male-female ratio was 1.37∶1. The high-risk ages were 20-49. Maxilla-mandible ratio was 1.37∶1. Conclusions: There was no gender preference for odontogenic tumors in Jilin Province area in the 57 years. The majority tumors occurred in the radicular. The most common pathological type was ameloblastoma. As for odontogenic cysts, males showed a higher incidence and the majority cysts occurred in the maxilla. The most common pathological type was radicular cysts.

Complete Healing of a Large Cystic Lesion Following Root Canal Treatment with Concurrent Surgical Drainage: A Case Report with 14-Year Follow-Up.

We describe complete healing of an extensive cystic lesion by using a conservative approach: root canal treatment with concurrent surgical drainage. A silicone Foley catheter drain was modified into a surgical drainage stent, which was then used for 4 weeks. Disinfection of the root canal was achieved by the use of hand files and irrigation with 5.25% NaOCl for a minimum of 30 minutes. The irrigant changes were performed at 5-minute intervals, and no intracanal dressing was used. At subsequent follow-up examinations, cone-beam computed tomography and periapical radiographs confirmed that complete healing had occurred around the periapical and lateral areas of affected teeth. This case report indicates the potential for healing of large cystic lesions by nonsurgical root canal treatment.

Anterior lingual mandibular bone depression: differential diagnosis of periapical inflammatory disorders.

Lingual mandibular bone depressions mainly affect the posterior region of the mandible. Depressions in the anterior region are rare, frequently posing difficulties in diagnosis. The aim of this article is to present a case of an anterior lingual mandibular bone depression (ALMBD) that was radiographically superimposed on the roots of anterior teeth. A 43-year-old man was referred for evaluation of a slight depression on the lingual surface of the anterior mandible. The depression was associated with a well-defined radiolucent area superimposed on the roots of the right canine and incisors. All teeth in the area proved to be vital, and cone beam computed tomography (CBCT) revealed a lingual depression in the area. The final diagnosis was an ALMBD, and the patient underwent clinical and radiographic follow-up examinations for 22 months that revealed no alterations in the area. When anterior mandibular radiolucencies are superimposed on the roots of the adjacent teeth, ALMBDs should be considered in the differential diagnosis along with periapical cysts and granulomas. Radiographic and CBCT analyses are useful to avoid unnecessary endodontic and surgical approaches.

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.

[The radicular cyst in the maxillary sinus encountered in the clinical otorhinolaryngological practice]. / Radikuliarnaia kista verkhnei cheliusti v praktike otorinolaringologa.

This article was designed to report the clinical case of the radicular cyst localized in the maxillary sinus of the 23 year-old man that had been detected before the surgical intervention was undertaken for its treatment. In the preceding visits of the patient to other medical settings, this condition was misinterpreted as a genuine (rhinogenic) cyst. It accounted for the choice of the inadequate surgical strategy for the management of this pathology. As a result, the patient experienced two relapse episodes of the disease. The thorough analysis of the patient's medical history and CT images of the sinus obtained during the 4 year follow up period allowed to establish the definitive diagnosis of odontogenic cyst of the upper jaw. The authors present a brief overview of the relevant scientific literature concerning etiology and pathogenesis as well as the methods of diagnostics and treatment of radicular cyst of the upper jaw.

Markers of proliferation and cytokeratins in the differential diagnosis of jaw cysts.

We conducted a retrospective study to analyze the histologic and immunohistochemical findings in three main types of odontogenic cyst. We studied 90 archived cystic jaw lesions: 30 dentigerous cysts, 30 keratocystic odontogenic tumors, and 30 radicular cysts. The cyst types were identified on the basis of clinical, radiologic, and histopathologic findings. Immunohistochemical analyses included staining with Ki-67, p53, epidermal growth factor receptor (EGFR), cytokeratin (CK) 8, CK14, CK17, and CK18. Cell immunopositivity was evaluated for the entire epithelium. The criteria for Ki-67 and p53 positivity were dense and/or faint nuclear staining, and cells were considered EGFR-positive if they exhibited membrane staining and/or cytoplasm staining. For the cytokeratins, cells exhibiting cytoplasm staining were considered positive. Five representative fields of each lesion were selected and identified in each of the Ki-67- and p53-stained slides. We found a statistically significant difference in the ratio of Ki-67-positive cells in the entire layer between the keratocystic odontogenic tumors and both the dentigerous cysts and the radicular cysts. A statistically significant difference was observed in the ratio of p53-positive cells between the keratocystic odontogenic tumors and the radicular cysts. Cytokeratins proved to be useful in differentiating radicular cysts from other types of cystic jaw lesions because of their CK8-positive and CK17-negative immunolabeling.

Odontogenic Cysts and Neoplasms.

This article reviews a myriad of common and uncommon odontogenic cysts and tumors. The clinical presentation, gross and microscopic features, differential diagnosis, prognosis, and diagnostic pitfalls are addressed for inflammatory cysts (periapical cyst, mandibular infected buccal cyst/paradental cyst), developmental cysts (dentigerous, lateral periodontal, glandular odontogenic, orthokeratinized odontogenic cyst), benign tumors (keratocystic odontogenic tumor, ameloblastoma, adenomatoid odontogenic tumor, calcifying epithelial odontogenic tumor, ameloblastic fibroma and fibroodontoma, odontoma, squamous odontogenic tumor, calcifying cystic odontogenic tumor, primordial odontogenic tumor, central odontogenic fibroma, and odontogenic myxomas), and malignant tumors (clear cell odontogenic carcinoma, ameloblastic carcinoma, ameloblastic fibrosarcoma).

Retrospective analysis of nonendodontic periapical lesions misdiagnosed as endodontic apical periodontitis lesions in a population of Taiwanese patients.

OBJECTIVE: We aimed to evaluate nonendodontic periapical lesions clinically misdiagnosed as endodontic periapical pathoses in a population of Taiwanese patients. MATERIALS AND METHODS: Cases (2000-2014) of histopathological diagnoses of nonendodontic periapical lesions were retrieved from all cases with a clinical diagnosis of radicular cyst, apical granuloma, or apical periodontitis in the institution. These cases were regarded as misdiagnosed nonendodontic periapical lesions, of which the types and frequencies, in addition to the demographic data, were determined. RESULTS: Four thousand and four specimens were clinically diagnosed as endodontically associated pathoses, of which 118 cases (2.95%) received a histopathological diagnosis of a nonendodontic pathologic entity, the most frequent lesion being keratocystic odontogenic tumor (KCOT, n = 38, 32.20%), followed by fibro-osseous lesion (n = 18, 15.25%), and dentigerous cyst (n = 13, 11.02%). Nine malignant lesions in the periapical area [squamous cell carcinoma (n = 7, 5.93%), adenoid cystic carcinoma (n = 1, 0.85%), and Langerhans cell histiocytosis (n = 1, 0.85%)] were also noted. CONCLUSIONS: A wide variety of histopathological diagnoses, including benign odontogenic and non-odontogenic cystic and tumorous lesions and infectious diseases, as well as malignant lesions, was noted in these 118 cases of nonendodontic periapical lesions. Squamous cell carcinoma was the most predominant malignancy of nonendodontic periapical lesions misdiagnosed as apical periodontitis lesions from imaging examination overlooking the clinical findings. CLINICAL RELEVANCE: The current data form a useful basis for clinicopathological investigation and educational teaching regarding nonendodontic periapical lesions misdiagnosed as endodontic apical periodontitis lesions.

The root of the problem: Occurrence of typical and atypical periapical pathoses.

BACKGROUND: A preponderance of periapical radiolucencies are of inflammatory etiology (radicular cysts or periapical granulomas) secondary to pulpal disease. In some instances, however, a suspected periapical inflammatory lesion is not a consequence of pulpal disease but instead represents a lesion of noninflammatory origin. The differential diagnosis for such lesions is broad, ranging from odontogenic cysts and tumors to metastatic disease. As the biological behavior of such lesions is varied, the distinction between inflammatory odontogenic periapical lesions and lesions of noninflammatory origin in a periapical location is critical. METHODS: A retrospective study of 5,993 archival periapical biopsies over a span of 15 years from the database of the Oral Pathology Biopsy Service in the Henry M. Goldman School of Dental Medicine at Boston University recorded the incidence of various lesions in a periapical location. RESULTS: Of the cases studied, 97.2% represented lesions of inflammatory origin with histopathologic diagnoses as follows: periapical granuloma (60.0%), radicular cyst (36.7%), periapical fibrous scar (0.27 %), and periapical abscess (0.23 %). The remaining 2.8% cases were lesions of noninflammatory origin with histopathologic diagnoses of odontogenic keratocyst (also known as keratocystic odontogenic tumor), benign fibro-osseous lesions, and ameloblastoma. One patient had Langerhans cell disease, and 1 had central giant cell granuloma. CONCLUSIONS: Although most periapical specimens biopsied represented expected inflammatory periapical lesions, the biological behavior of underdiagnosed lesions may have considerable consequences for both the patient and the clinician. PRACTICAL IMPLICATIONS: This article serves to inform clinicians regarding the diversity of lesions arising in the periapical region of the jaws, to assist in the formulation of differential diagnoses, and to highlight the importance of submission of lesional tissue for histopathologic evaluation and definitive diagnosis when biopsy is clinically indicated.