Metaplasia and degeneration in odontogenic cysts in man

Assessment of MUC5AC and MUC2 Immunoexpression in Glandular Odontogenic Cysts, Dentigerous Cysts, and Mucoepidermoid Carcinomas

Glandular odontogenic cysts (GOCs) and dentigerous cysts may show mucous metaplasia. Central mucoepidermoid carcinoma is very rare and mostly associated with dental cysts. It is hypothesized that odontogenic cysts showing mucus differentiation in their lining, have a propensity to transform into MEC. The present study is the first attempt to explore the relationship between odontogenic cysts [GOCs and dentigerous cysts with mucus metaplasia (DCMM)] and MEC by evaluating immunoexpression of MUC5AC and MUC2. Immunoexpression of MUC5AC and MUC2 was evaluated semiquantitatively in GOCs (20 cases), DCMMs (20 cases), and MECs (20 cases). The percentage of positive cells, intensity, and localization of immunoexpression were assessed for each marker in all cases. Of GOCs, DCMMs, and MECs cases, 85%, 70%, and 80%, respectively, were immunopositive for MUC5AC. Strong cytoplasmic immunoreactivity for MUC5AC was noted, particularly in mucous cells present diffusely within MECs. However, the immunoreactivity was limited to the epithelial lining of GOCs and DCMMs. Most of the MECs (60%) showed more than 25% positivity for MUC5AC, followed by GOCs, and the least in DMMCs. Mild cytoplasmic and nuclear positivity of MUC2 was noted only in epithelial lining cells of 70% GOCs and 45% DCMMs. Whereas, 55% of MECs displayed moderate to strong cytoplasmic and membranous immunopositivity for MUC2 exclusively within mucous cells. As MECs showed strong MUC5AC immunoreactivity in mucous cells, immunoexpression of MUC5AC in odontogenic cysts with mucus cells can possibly explain the pathogenesis of MEC from cysts. However, the variable expression of MUC2 did not give any strong evidence regarding its role as a marker.

Metamorphosis of Dentigerous cyst: A case Series with Insight into Molecular Profiling

The objective of this study was to review the clinical, radiologic, and histologic aspects of cases of dentigerous cysts metamorphosing into different entities along with comments on the molecular factors involved in the process. A series comprising 8 cases of dentigerous cysts was performed retrospectively along with a comprehensive literature review. Two cases of dentigerous cyst converting into mucous metaplasia were included, out of which one case was transformed into ameloblastoma after a year. The other two cases were reported as acanthomatous and unicystic ameloblastoma, whereas four transitioned to AOT. The complete review of cases and literature with molecular profiling concluded that the lining of dentigerous cysts has the potential for transforming into benign odontogenic tumors. Therefore, a careful clinical and histopathological examination is crucial for the correct diagnosis. Also, a thorough molecular understanding of the cystic lining is required.

Intraosseous Mucoepidermoid Carcinoma of the Mandible Detected as an Asymptomatic Swelling

Intraosseous mucoepidermoid carcinoma (IMEC) is a rare neoplasm of the jawbones. Although hypotheses focused on the malignant transformation of the epithelial mucosa of odontogenic cysts or ectopic salivary gland tissue have been suggested, the etiology of the disease is still unclear. It is more frequent in middle-aged individuals, has a slight female predilection, and is more common in the mandible than in the maxilla. Cortical enlargement is the most common symptom, while some lesions are detected by coincidence on radiography. This paper reports an IMEC of the mandible of a 35-year-old female, possibly arising from the remains of an odontogenic cyst associated with an unerupted mandibular molar, which was operated in an external center 5 years ago before IMEC diagnosis.

Malignant tumours mimicking periapical lesions: A report of three cases and literature review

Apical periodontitis shows radiographic signs such as widening of the periodontal ligament and periapical radiolucency, which differ in extent depending on the stage of the lesion. However, other lesions can be associated with or coincidental to the apical region, representing developmental lesions and benign or malignant tumours. This article describes three cases of malignant tumours, a central mucoepidermoid carcinoma (CMEC), a chondroblast osteosarcoma and an osteosarcoma of the jaw (OSJ) that presented as periapical lesions. Endodontists must be aware of unsuccessful treatment, persistent pain, signs of paraesthesia, a rapid growth rate and delayed response to therapy associated with atypical features. Complementary examinations, such as biopsy and computed tomography, can allow the early diagnosis of malignant tumours, leading to a better prognosis and thus increased survival rates and improvement in quality of life.

Correlation of Pericoronal Radiolucency Around Impacted Mandibular Third Molars Using CBCT with Histopathological Diagnosis: A Prospective Study

Purpose:

This study aimed to correlate the pericoronal width surrounding impacted mandibular third molars with their histopathological findings.

Materials and Methods:

The present study included patients who were advised for extraction of impacted mandibular third molars with the pericoronal radiolucency radiographically. The CBCT scans were compared with histopathologic findings of the follicles.

Results:

Out of 70 patients evaluated histopathologically, 24 patients showed mild inflammatory changes, whereas 34 patients revealed cystic changes suggestive of a dentigerous cyst, followed by 12 patients showing evidence of calcifications in the pericoronal follicles. The dentigerous cyst was more likely to occur if the bucco-lingual width of the pericoronal radiolucency was 14.00-16.00mm, and calcifications were found to be most likely present if the buccolingual width was 12.00-14.00mm, both of which were statistically significant.

Conclusion:

CBCT can be a reliable tool in the evaluation of pericoronal follicular space, and the values in different dimensions can be an accurate predictor radiologically for the diagnosis of pathologies when compared to 2D imaging.

Odontogenic keratocyst with diverse variations: A rare case report

Rationale:

An odontogenic keratocyst (OKC) is a developmental odontogenic cyst lined by squamous epithelium having intrinsic growth potential. Hence, metaplastic changes such as the formation of mucous cells, ciliated cells, and hyaline bodies with ortho/para keratinisation have been known to create unusual histopathological variations.

Patient Concerns:

A 34-year-old male patient reported with swelling on the lower right side of the face and numbness on the overlying skin.

Diagnosis:

Based upon the histopathological findings, a final diagnosis of glandular odontogenic cyst with OKC was confirmed presenting mixed features of basal layer palisading squamous epithelium with goblet cells and satellite cysts appeared to be entrapped in the connective tissue wall.

Treatment:

Surgical enucleation of the cyst was done.

Outcomes:

No recurrence was reported in 1 year of follow-up.

Take-away Lessons:

Diverse variations appear within odontogenic cysts and tumours. The high recurrence rate and aggressive nature of the cyst, divulges appropriate treatment and long-term follow-up.

Dystrophic calcification and respiratory metaplasia in the epithelial lining of odontogenic cysts: a study of 362 odontogenic cysts in a Brazilian population and literature review

PURPOSE

Main study: undertake a histological study of odontogenic cysts (OC) to determine the prevalence of dystrophic calcification and metaplasia to respiratory epithelium on a Brazilian population.

LITERATURE REVIEW

to review the literature for studies that investigated the prevalence of respiratory metaplasia and dystrophic calcification on OC.

METHODS

Main study: a retrospective histopathological evaluation was made of the archives from a pathology laboratory. A total of 362 cases diagnosed as OC were identified; they were analyzed by two expert observers to determine the presence of dystrophic calcification and respiratory metaplasia. The association with sex, age and anatomic location was performed through statistical analysis.

LITERATURE REVIEW

a critical literature review was undertaken. Two main electronic databases (PubMed and LILACS) were searched. Retrospective studies of histological evaluation that determined the prevalence of epithelial metaplasia and dystrophic calcification on OC, with at least 10 cases, were included; their findings were summarized and discussed.

RESULTS

Main study: the histological evaluation of OC revealed the presence of respiratory epithelium in 25 cases (6.9%) and dystrophic calcification in 24 cases (6.6%). Positive association was found to dystrophic calcification on residual cyst and age; respiratory metaplasia on OC and sex; respiratory metaplasia on residual cyst and gnatic bone; respiratory metaplasia in OC and gnatic bone; dystrophic calcification in OC and anatomic site of mandible.

LITERATURE REVIEW

eleven studies were included in the literature review, and respiratory metaplasia ranged from 0.0% to 19.2% while dystrophic calcification ranged from 2.5% to 40.5%.

CONCLUSIONS

the histological evaluation of this study found 6.9% of prevalence of respiratory metaplasia and 6.6% of dystrophic calcification, which is in accordance with the literature reviewed. Therefore, these phenomena must be taken into account in routine diagnosis services.

Ameloblastoma with mucous cells: A clinicopathological, BRAF mutation, and MAML2 rearrangement study

OBJECTIVES

To investigate the clinicopathological features, BRAF V600E mutation, and MAML2 rearrangement of ameloblastoma with mucous cell differentiation.

MATERIALS AND METHODS

Five cases of ameloblastoma with mucous cell differentiation were retrospectively studied. Clinicopathological features, BRAF V600E mutation, and MAML2 rearrangement were analyzed. Follow-up information was available for all cases.

RESULTS

Of five cases, two cases were male and three were female, aged 18-55 years. Four cases were located in the mandible and one case in the maxilla. Histologically, four of the five cases (80%) presented with cystic features and three of the five cases (60%) with varying degrees of squamous metaplasia. The mucous cells were located in the epithelial islands or the luminal aspect of the cystic cavities. The BRAF V600E mutation was found in three of five cases (60%). All the cases showed no MAML2 rearrangement. Two cases were recurrent lesions, and one case had a local recurrence during the follow-up.

CONCLUSIONS

Ameloblastoma with mucous cell differentiation is closely related to the cystic features, squamous metaplasia, and shows a high prevalence of BRAF V600E mutation. The absence of MAML2 rearrangement reveals that ameloblastoma with mucous cell differentiation and central mucoepidermoid carcinoma (MEC) are two distinct tumor entities.

Relative frequency of dentigerous cyst in Iranian population: A 20-year retrospective study

Purpose

Dentigerous cyst (DC) is the most common type of developmental odontogenic cysts which apparently develops via accumulation of fluid between the reduced enamel epithelium and crown of the tooth. The aim of this study is to analyze the frequency of DC in Iranian population.

Materials and Methods

The files of oral pathology, Shahid Beheshti University of Medical Sciences, served as the source of the materials from 1992 to 2012 for this study. All lesions diagnosed as DCs were subjected to microscopic reevaluation. Patient's age, sex, location, and microscopic characteristics were recorded. Based on these data, a descriptive statistical analysis was performed using SPSS 19 software (IBM SPSS Statistics 19, New York, United States) and the results with P < 0.05 were considered as significant.

Results

DC accounted for 34.37% of all odontogenic cysts of the jaws during the 20-year period. The mean age of patients was 24.72 years and most cases are diagnosed in the second and third decades of life. The male-to-female ratio was 1.52. About 73.89% of all lesions had occurred in the mandible and 26.11% in maxilla. DCs showed Vickers and Gorlin (ameloblastomatous) changes in 2.36% of cases. The mean age was significantly lower in the premolar area (P = 0.00).

Conclusion

Age, sex, and location of DCs in Iranian population are similar to previous studies. In addition, the age of occurrence for this lesion in the premolar region was relatively lower than at other sites. Although the risk of ameloblastic change is low, it should be considered as an important issue.

Mucous Cell Prosoplasia in Oral Pathologies: A Brief Review

One of the enigmas in cell differentiation process is prosoplasia, which is contemplated as forward differentiation. A well-known example of prosoplastic switch is mucous cell prosoplasia, which is the transformation of a simple squamous epithelial cell into mucous secreting cell. Numerous theories have been proposed for histogenesis of this phenomenon, which are comprehensively discussed in the present paper. Oral pathologies like odontogenic cysts and salivary gland tumours show mucous prosoplasia quite often; sometimes leading to diagnostic difficulties. In the present paper, efforts have been made to comprehensively discuss diverse aspects of mucous prosoplasia like histogenesis, theories and diagnostic importance in various oral pathologies.

Metaplastic changes in the epithelium of radicular cysts: A series of 711 cases

Background

This study was aimed to evaluate the prevalence of metaplastic changes in the epithelium of radicular cysts and to investigate how they relate to the clinical and radiographic characteristics of the cysts, based on a large series of radicular cysts.

Material and Methods

Biopsies of cysts of endodontic origin that were examined at the Department of Oral Pathology between 2004 and 2011 have been re-evaluated for this study. Only cases that were re-confirmed with clinical and histological diagnoses of a radicular or residual radicular cyst were included. The included cases were evaluated for the prevalence of metaplastic changes in the form of mucous secreting cells (MSC) or ciliated cells (CC). The relations between the metaplastic changes and the cyst type (radicular or residual radicular), as well as demographic, clinical and radiographic parameters, were statistically evaluated using Fischer and chi-square tests. Significance was set at p<0.05.

Results

A total of 711 cysts were included: 677 were radicular cysts (95%) and 34 (5%) were residual radicular cysts. 23 cases had histopathological diagnoses other than radicular or residual radicular cysts and were excluded from the study. MSC were present in 47 (6.6%) cysts. MSC were significantly more common in residual radicular cysts than in radicular cysts [8 (23.5%) and 39 (5.8%), respectively; p<0.001]. MSC-containing cysts were commonly found in asymptomatic patients (10.5%, p<0.001), and usually presented with well-defined radiographic borders (7.2%, p<0.05). CC were present in 34 (4.8%) cysts, with a markedly high prevalence in the maxillary molar sextant (15%, p<0.001).

Conclusions

In the epithelium of radicular and residual radicular cysts the presence of specific metaplastic changes may be related to cyst type, symptomatology, radiographic findings and tooth location.

Key words:Radicular cyst, metaplasia, mucous secreting cells, ciliated cells.

Histopathological and Radiographic Analysis of Dental Follicle of Impacted Teeth Using Modified Gallego's Stain

INTRODUCTION

In the WHO classification of odontogenic tumours, hard tissue formation has been considered as a sub-classification however, this parameter has not been much explored in dental follicle in literature. Epithelial-mesenchymal interactions play an important role in odontogenesis and its associated pathologies; therefore research on dental follicle should also include mesenchymal components along with epithelial components. Additionally, special stains to identify the nature of such depositions in dental follicle have been less explored. Modified Gallego's stain is such an example which has not been tried in odontogenic lesions which makes this study unique.

AIM

Aim of this study was to study histopathological variations in dental follicle, the nature of calcification and depositions using Modified Gallego's stain and to correlate histological features of dental follicle with pericoronal width radiographically.

MATERIALS AND METHODS

A prospective histological study of the dental follicles of 50 impacted teeth was carried out to microscopically evaluate the dental follicular tissues for pathological changes, and to correlate it with pericoronal radiolucency. Impacted teeth with pericoronal radiographic width less than 3mm were included in the study and symptomatic teeth were excluded. Further Modified Gallego stain was used to differentiate the nature of hard tissue formation in dental follicle tissues.

RESULTS

Dental follicle histologically showed pathological changes resembling dentigerous cyst, ameloblastoma, odontogenic fibroma (Simple and WHO Type), clear cell odontogenic tumour, neurofibroma, neurilemmoma and mucoepidermoid carcinoma.

CONCLUSION

The dental follicle surrounding an impacted tooth has the potential to differentiate into a wide variety of tissue types, and thus shows the potential for cyst and tumour development which was observed in this study in most of the specimens with normal follicular width radiographically.

Odontogenic Cysts and Tumors

This article presents various odontogenic cysts and tumors, including periapical cysts, dentigerous cysts, odontogenic keratocysts, orthokeratinized odontogenic cysts, lateral periodontal cysts, glandular odontogenic cysts, ameloblastomas, clear cell odontogenic carcinomas, adenomatoid odontogenic tumors, calcifying epithelial odontogenic tumors, squamous odontogenic tumors, ameloblastic fibromas, ameloblastic fibro-odontomas, odontomas, calcifying cystic odontogenic tumors, and odontogenic myxomas. The authors provide an overview of these cysts and tumors, with microsopic features, gross features, differential diagnosis, prognosis, and potential diagnostic pitfalls.

Primary intraosseous mucoepidermoid carcinoma of the jaw: Reappraisal of The MD Anderson Cancer Center experience

BACKGROUND

Mucoepidermoid carcinoma arises from major or minor salivary glands, making up 10% of salivary gland tumors. Intraosseous mucoepidermoid carcinomas are rare, and make up only 2% to 3% of all mucoepidermoid carcinomas. The t(11;19) and its CRTC1-MAML2 fusion gene transcript have been identified in mucoepidermoid carcinoma and are associated with a subset of mucoepidermoid carcinomas. The extent to which the transcript influences disease features and patient survival is unclear.

METHODS

We conducted a retrospective analysis of records for clinical features, surgical interventions, and prognoses. Reverse transcriptase-polymerase chain reaction (RT-PCR) and fluorescence in situ hybridization (FISH) used to assess the t(11;19) fusion gene in intraosseous mucoepidermoid carcinoma.

RESULTS

Twenty-five patients with intraosseous mucoepidermoid carcinoma treated between 1998 and 2013 were identified. The t(11;19) fusion gene transcript CRTC1-MAML2 manifested in 9 intraosseous mucoepidermoid carcinomas, whereas is was not detected in another 9 intraosseous carcinomas. Although the incidence of this fusion in mucoepidermoid carcinoma varies, it is generally accepted that more than 50% of this entity manifest the CRTC1-MAML2.

CONCLUSION

Intraosseous mucoepidermoid carcinoma diagnosis should be based on clinical and pathologic manifestations and complete resection is the first choice for patient treatment. The need for neck dissection and adjuvant treatment are debatable. Radiotherapy may improve prognosis and may be recommended in the postoperative period. Primary intraosseous mucoepidermoid carcinoma can manifest the fusion transcript in a subset of tumors. © 2015 Wiley Periodicals, Inc. Head Neck 38: E1312-E1317, 2016.

Biochemical and Cytological Comparison of Keratocystic Odontogenic Tumours to Nonkeratinising Odontogenic Cysts Fluid

AIM

To evaluate the levels of albumin, prealbumin, total protein, inorganic phosphate and presence of keratinocytes in the cystic fluid for the diagnosis and appropriate treatment planning of keratocystic odontogenic tumours and other non keratinizing odontogenic cysts.

MATERIALS AND METHODS

Fifteen keratocystic odontogenic tumour and 15 controls were studied. The cystic fluid was aspirated and analysed to determine the levels of albumin, prealbumin, total protein, inorganic phosphate and the presence of keratinocytes. The data collected was statistically evaluated using Mann Whitney U-Test and Student's t-test.

RESULTS

A highly significant difference (p<0.0001) was seen when a comparison of Prealbumin, total protein, inorganic phosphate and presence of keratinocytes was made between keratocystic odontogenic tumour and non keratinizing odontogenic cysts. The presence of albumin also showed a significant difference (p<0.01).

CONCLUSION

A combined analysis of total protein, albumin, prealbumin, inorganic phosphorous and detection of epithelial squames may be used as a diagnostic adjunct in the preoperative diagnosis of keratocystic odontogenic tumour in a minimally invasive and highly accurate fashion.

Keratin metaplasia in the epithelial lining of odontogenic cysts

Objective:

To find the prevalence of keratin metaplasia and its relation with clinico-pathological profile of the odontogenic cyst.

Materials and Methods:

Odontogenic cysts were studied histologically with special stains to identify the presence of keratin and compared with various parameters such as underlying connective tissue inflammation, average epithelial thickness, and site of the cyst, type of the cyst, age and the sex of the patient.

Results:

Of 71 cases of various odontogenic cysts, 26 (36.6%) cases exhibited keratinization in the epithelial lining. In cysts with severe inflammation there is absence of keratinization.

Conclusions:

This study reveals higher prevalence of keratin metaplasia in the odontogenic cysts. Furthermore, inflammation is found to be one of factor influencing keratin metaplasia.

Orthokeratinized odontogenic cysts presenting as a periapical lesion: report of a case and literature review

INTRODUCTION

Inflammatory cysts, granulomas, abscesses, and fibrous scars represent most periapical radiolucencies. However, other less common lesions, such as orthokeratinized odontogenic cysts (OOCs), can be found at this region, and they deserve to be discussed because the prognosis for an OOC is different from that expected for the ordinary inflammatory periapical diseases.

METHODS

An interesting case of OOC associated with a nonvital tooth in a 40-year-old woman is described. After a previous clinical diagnosis of a radicular cyst, the tooth was extracted, and the lesion was enucleated and submitted to microscopy examination.

RESULTS

Because of the detection of an orthokeratinized epithelium lining, a diagnosis of OOC was concluded. After 2 years of periodic follow-up, no signs of recurrence were detected.

CONCLUSIONS

The presence of keratin in radicular lesions must be carefully evaluated to eliminate the diagnosis of lesions with more aggressive behavior, such as an OOC or even a keratocystic odontogenic tumor. Hence, histopathologic examination is mandatory to confirm the type of lesion and to differentiate other pathologic conditions, therefore establishing patients' prognoses precisely.

A case of mucoepidermoid carcinoma associated with maxillary cyst

We report a case of a mucoepidermoid carcinoma associated with a maxillary cyst. The patient was an 18-year-old man presenting with the chief complaint of left buccal swelling. The left maxillary third molar was semi-impacted in the direction of the crown on the buccal side. Orthopantomography revealed a cystic radiolucency extending over a wide area, ranging from the left maxilla to the maxillary sinus and nasal cavity. Computed tomography revealed a multilocular lesion surrounded by a thin shell of bone. Biopsy findings revealed a cystic lesion, but the cause could not be identified preoperatively. The cystic lesion was resected under general anesthesia. The lesion was multilocular and surrounded by a bone shell, and had expanded into the maxillary sinus. At the same time, indurated soft tissue adhering strongly to the palatine bone on the inferior palatine side of the lesion was resected. Histopathological examination showed a cystic lesion and mucoepidermoid carcinoma. An additional resection was planned and the maxilla partially resected. Mucoepidermoid carcinomas usually occur in the parotid and minor salivary glands, but in rare cases appear in the center of a jaw bone, almost always in the mandible. In the present case, the carcinoma was associated with a cystic lesion believed to have developed from maxillary bone and involved an impacted tooth adjacent to the tumor. This suggested a central mucoepidermoid carcinoma in the maxillary cyst. Postoperatively, the missing teeth have been replaced with a denture and the course has been good, with no recurrences or metastases identified.

Predominantly cystic central mucoepidermoid carcinoma developing from a previously diagnosed dentigerous cyst: case report and review of the literature

Primary intraosseous mucoepidermoid carcinoma of the jawbones is an extremely rare malignant salivary gland tumour constituting 2-4.3% of all the reported mucoepidermoid carcinomas. We report a case of intraosseous mucoepidermoid carcinoma of the mandible in an 80-year old female patient developing from a previously diagnosed dentigerous cyst. An excisional biopsy was performed and the histopathological features confirmed low grade-cystic intraosseous mucoepidermoid carcinoma. The origin of central mucoepidermoid carcinoma could be suggested to be from the epithelial lining of previously diagnosed dentigerous cyst. Thus, emphasizing the need for careful examination of the entire excision specimen to rule out such neoplastic transformation of epithelial lining of odontogenic cyst and provide appropriate and effective treatment.

A study on dentigerous cystic changes with radiographically normal impacted mandibular third molars

BACKGROUND

Dentigerous cyst develops in the follicular tissue surrounding the impacted lower third molar. A study was carried out to know the incidence of Association of Dentigerous cyst with radiographically normal impacted lower third molars and to draw the attention of the Oral Surgeons towards the prophylactic removal of impacted third molars.

METHODS

A prospective study was done on 30 patients with impacted lower third molars which were indicated for extraction. The follicle tissue surrounding the impacted tooth was subjected for histopathologic investigations. Only those teeth with a radiographic finding of pericoronal space of less than 2.5 mm were considered. Two Oral Pathologists reviewed the slides for any changes suggestive of cystic pathology.

RESULTS

Pathologic changes suggestive of Dentigerous cyst was found in 7 of the 30 follicular tissue sent for histopathologic testing. It was found to be statistically significant (P < 0.001).

CONCLUSION

This study shows statistically high incidence of Dentigerous cyst association with radiographically normal impacted lower third molar teeth. Hence the Oral and Maxillofacial surgeons should consider histopathologic evaluation and radiographic diagnosis in the management of impacted lower third molars. Prophylactic extractions of normal impacted lower third molars should be considered as a treatment option.

Intraosseous carcinoma of the jaws--a clinicopathologic review. Part I: Metastatic and salivary-type carcinomas

This is the first part of a 3-part comprehensive review of intraosseous carcinoma of the jaws. We have outlined 4 groups of intraosseous carcinoma of the jaws (metastatic, salivary-type, odontogenic, and primary intraosseous carcinoma), emphasizing the need for accurate diagnosis and the problems associated with changing classification systems, standardization of diagnostic criteria and nomenclature, and the accuracy of existing literature. In this first part, the features of metastatic and the very rare salivary-type carcinomas of the jaws are examined with particular emphasis on histologic and immunohistochemical characteristics, diagnostic difficulties, and uncertainties.

Mixed periapical lesion: differential diagnosis of a case

A radicular cyst associated with carious teeth is a very common odontogenic lesion in the oral cavity, but calcifications in residual radicular cysts are quite rare. We report one such case where a routine pre-implant radiographic assessment revealed a mixed periapical radiopaque radiolucent lesion in the right maxillary central incisor region. Histological and radiographic studies show that there is a slow increase in the mineralized deposits within the cyst lumen with time. This becomes prominent histochemically in cysts more than 8 years old and radiographically 6 years later, as seen in our case. In this paper we would like to highlight the importance of a residual radicular cyst with calcifications in the differential diagnosis of a mixed periapical radiopaque radiolucent lesion.

Aggressive growth and neoplastic potential of dentigerous cysts with particular reference to central mucoepidermoid carcinoma

Epidermoid carcinoma and mucoepidermoid carcinoma that arise centrally within the jaws are often associated with dental cysts. Central mucoepidermoid carcinoma of the jaws is rare, and usually presents in the fourth to eighth decades; we know of only 7 cases that have been described in children younger than 16. Here we describe a central mucoepidermoid carcinoma in an 8-year-old girl that arose from a dentigerous cyst associated with an unerupted mandibular molar.

Mucous cell differentiation in a unicystic ameloblastoma

The authors report a case of unicystic ameloblastoma with mucous cell differentiation in the right mandible of a 24-year-old Korean male who suffered from painful swelling for 2 months. A radiograph showed a well-circumscribed radiolucent lesion between the root of the right first premolar and the first molar tooth. Microscopic examination revealed the cystic lesion was lined with ameloblastic epithelium and goblet cells in the epithelium. The mucous cells reacted positively to mucicarmine stain. The possible pathogenic mechanism of this case reflects the pluripotential character of the odontogenic epithelium. The prognosis is probably that expected for conventional unicystic ameloblastoma.

Glandular odontogenic cyst in China: report of 12 cases and immunohistochemical study

OBJECTIVE

The purpose of this study was to present 12 additional cases of glandular odontogenic cyst (GOC) in the Department of Oral Pathology, School of Stomatology, Wuhan University, People's Republic of China, and to investigate their immunohistochemical cytokeratins (CKs) expression in the epithelial components.

METHODS

A total of 12 GOCs were reviewed clinically and radiographically, and immunohistologic CKs AE1, 7, 8/18, 10/13, 14, 16, 19 and 20 were performed by using a standard biotin-streptavidin immunoperoxidase technique on paraffin sections.

RESULTS

The present series showed that eight occurred in males and four in females. The mean age was 37.6 years with a peak incidence occurring in the third decades (six of 12). Mandibles were more affected than maxillas (7:5), especially anterior mandible (four of seven). Radiographically, ratio multilocular to unilocular radiolucencies was 5:7 usually with well-defined borders. Histologically, cystic spaces were lined by non-keratinized stratified epithelia containing focal plaque-like or whirlpool-like thickenings; surface epithelial layer-containing eosinophilic cuboidal cells; mucous cells; and mucin pools of microcystic areas in the epithelium. Immunohistochemistry showed that epithelium of GOCs stained for CKs AE1, 7, 8/18, 10/13, 14 and 19 with slight changes in their patterns, and no reaction to CKs 16 and 20.

CONCLUSIONS

Most clinical and histologic features in this study were analogous to those reported west population, although with slight difference between them. Histologically, the morphology of the epithelium strongly suggested an odontogenic origin, and CKs expression of GOC was similar to that of odontogenic epithelium, suggesting histochemically that GOC might be derived from odontogenic epithelium.

An unusual odontogenic cyst with diverse histologic features

An unusual odontogenic cyst, which was originally believed to be a clinical dentigerous cyst associated with an impacted mandibular third molar, was found histologically to demonstrate the characteristics of a glandular odontogenic cyst with para- and orthokeratinization. These histologic diversities were interpreted as a reflection of the pluripotentiality of the epithelial remnants of the mandibular third molars or dentigerous cyst epithelium. It is possible that it has the capacity to induce the formation of cysts in both squamous and glandular epithelium.

Mucous and ciliated cell metaplasia in epithelial linings of odontogenic inflammatory and developmental cysts

The incidence of mucous and ciliated cells in epithelial linings was examined among odontogenic inflammatory cysts (radicular cysts) and developmental cysts (dentigerous and primordial cysts). Mucous cells were found in 20.8% of all cysts examined, while ciliated cells were found in 11.4%; however, ciliated cells were always accompanied by mucous cells. The incidence of mucous cells in radicular cysts and dentigerous cysts and that of ciliated cells in radicular cysts was higher in the maxilla than in the mandible, while the incidence of mucous cells in primordial cysts and that of ciliated cells in dentigerous cysts and primordial cysts was higher in the mandible than in the maxilla. The present results regarding mucous cells and ciliated cells in the epithelial linings of intraosseous odontogenic cysts indicate a metaplasic origin, but the cause and biological significance of this phenomenon is not known. Mucous cells were present in the surface layer of epithelial linings, and intraepithelial gland-like structures lined with mucous cells were observed in the hyperplastic regions of epithelial linings of several radicular and dentigerous cysts. Such gland-like structures lined by mucous cells in the thickened epithelial lining, which have not been demonstrated previously, resembled the glandular structures of "glandular odontogenic cysts".

Cytokeratin expression patterns in jaw cyst linings with metaplastic epithelium

BACKGROUND

Cytokeratin (CK) expression patterns have been studied in numerous intact and diseased oral tissues. However, CK expression in metaplastic squamous cells has not been explored in depth and the origin of metaplastic epithelial linings of the jaw cysts has not been sufficiently investigated.

METHODS

We examined CK expression in 46 postoperative maxillary cysts (POMCs) which were lined with pseudostratified columnar cells only, columnar and squamous cells, and squamous cells only, in 13, 30 and 3 cases, respectively.

RESULTS

The expression of CK8, CK13 and CK18 were observed in 39, 9 and all 43 of the columnar epithelial linings, respectively. Metaplastic squamous epithelia expressed more CK13, and less CK18 and CK8. Of the 33 metaplastic linings, 24 expressed CK8, 23 CK13 and 26 linings expressed CK18. The patterns of expression of CK13 and CK18 observed were CK18(+)-CK13(-) in 10 metaplastic linings, CK18(+)-CK13(+) in 16, and CK18(-)-CK13(+) in 7. The expression of CK13- and CK18-mRNA was generally correlated with level of protein expressed. CK18-mRNA expression was observed by in situ hybridization, not only in the 26 metaplastic linings which were positive for CK18 protein, but also in five of the seven metaplastic linings which did not express CK18 protein. In addition, RT-PCR revealed an expression of CK18-mRNA in all metaplastic squamous linings, although the expression level was weaker than that in the columnar epithelial linings. The CK13-mRNA was expressed inversely to the CK18-mRNA.

CONCLUSIONS

These results indicate that CK18-mRNA is preserved through metaplasia, although the protein expression decreased. Metaplastic squamous cells differentiate with a decrease of CK18 and an increase of CK13 expression.

Expression of cytokeratins (CKs) 8, 13 and 18 and their mRNA in epithelial linings of radicular cysts: implication for the same CK profiles as nasal columnar epithelium in squamous epithelial lining

OBJECTIVE

Our objective was to specify cytokeratin (CK) patterns in lining epithelia of radicular cysts which are sometime lined with ciliated columnar epithelia as seen in the nasal epithelia.

MATERIALS AND METHODS

We examined the CK expression in 52 radicular cysts obtained from 32 maxillary and 20 mandibular lesions and investigated CK-mRNA expression using in situ hybridization in 24 maxillary and 13 mandibular cysts and reverse transcription-polymerase chain reaction (RT-PCR) in 24 maxillary cysts.

RESULTS

Of the maxillary cysts, 20, 29 and 19 squamous epithelial linings were positive for CK8, CK13 and CK18, respectively; of the mandibular cysts, 10, 20 and 11 linings were positive for these CKs, respectively. The expression patterns of CK18(+)-CK13(-), CK18(+)-CK13(+) and CK18(-)-CK13(+) were observed in 3, 16 and 13 linings of the maxillary cysts and 0, 11 and 9 linings of the mandibular cysts, respectively. In situ hybridization revealed the expression of CK18-mRNA in 9 and 4 linings of 24 maxillary and 13 mandibular cysts examined, respectively. With RT-PCR, we explored that both CK18- and CK13-mRNA were expressed not only in the normal nasal and gingival epithelia but also in the examined maxillary cyst linings although their expression levels differed correlating with the difference in CK staining.

CONCLUSION

It is concluded that CK13- and CK18-mRNA are constitutively expressed in columnar and squamous epithelial cells, respectively, and that the variant CK expression patterns with CK18-mRNA expression in maxillary radicular cysts are indicative of the possibility of phenotypic transformation in the cyst linings.

Intraosseous salivary tissue: jawbone examples of choristomas, hamartomas, embryonic rests, and inflammatory entrapment: another histogenetic source for intraosseous adenocarcinoma

PROBLEM

Hundreds of primary salivary neoplasms have been found to be completely enclosed within the marrow spaces of the maxilla and mandible, yet nonneoplastic salivary tissue has never been convincingly identified within marrow, either separately or adjacent to such neoplasms. This situation has forced the acceptance of an inherently awkward odontogenic origin for all intramedullary salivary carcinomas and adenomas.

OBJECTIVE

The purpose of this study was to microscopically evaluate a large number of maxillofacial marrow samples for the presence of intramedullary salivary tissue.

STUDY DESIGN

We microscopically reviewed 5034 maxillofacial bone samples from the Latvala Inflammatory Bone Registry for evidence of heterotopic salivary inclusions within the marrow tissues. Contributing surgeons were contacted for each identified case of intraosseous salivary tissue to assure that all submitted tissue was removed from within the marrow spaces rather than from overlying soft tissue.

RESULTS

Thirteen of 5034 marrow samples (0.3%) contained heterotopic acinic hamartomas, salivary choristomas, embryonic salivary rests, or entrapped surface glands. Four additional hamartomas of the condyle are described. We report also the chance finding of incipient odontogenic epithelial neoplasms (n = 6) and odontogenic epithelial rests (n = 84) within the fatty marrow and outside the periodontal ligament spaces, confirming that not all odontogenic neoplasms are necessarily of periodontal ligament origin.

CONCLUSION

The frequency rate for salivary choristomas, hamartomas, embryonic rests, and displaced surface glands within alveolar bone is no less than 2.6 of 1000 biopsied marrow samples. This provides an additional and quite logical histogenetic explanation for the presence of intraosseous salivary neoplasms.

Clinico-pathologic study of odontogenic cysts in a Mexican sample population

BACKGROUND

Odontogenic cysts are uncommon lesions that frequently behave agressively and attain a large size. Unfortunately, information on the relative incidence of these cysts from different populations is not abundant. In Mexico, for example, only a few examples have been reported. The aim of this study was to ascertain the frequency of odontogenic cysts in a Mexican sample and to compare these data with previously reported studies from other countries.

METHODS

The files of the Oral and Maxillofacial Pathology Diagnosis Service at the School of Dentistry at the Universidad Nacional Autónoma de México (UNAM) were reviewed and all accessions of odontogenic cysts were listed. Clinical and radiographic data were recorded and microscopic slides evaluated according to the most recent World Health Organization (WHO) classification (1992).

RESULTS

Three hundred and four cases of odontogenic cysts (55.9% male predominance) were found. The most frequent odontogenic cysts were the following: periapical cyst (38. 8%); dentigerous cyst (35.5%), and odontogenic keratocyst (18.8%). Periapical cyst was more frequent in females, and maxillary anterior teeth were most commonly involved. Dentigerous cysts appeared in males at a rate of 64.8%, this cyst found more frequently between the 1st and 2nd decades of life and in the molar zone. Odontogenic keratocyst was more frequent in males (59.6%), between the 2nd and 4th decades of life and more common in the molar zone.

CONCLUSIONS

More than 50% of the sample were aggressive cysts (dentigerous and keratocyst). Our results suggest that Mexican patients develop aggressive odontogenic cysts more commonly than other populations. Our figures point to the need for a precise diagnosis in order to institute the correct surgical procedure, prevent recurrence, and forestall more extensive tissue destruction.

Glandular odontogenic cyst (sialo-odontogenic cyst): report of two cases and literature review of 45 previously reported cases

The clinical, radiological, histopathological and immunohistochemical (cytokeratin) features of two cases of glandular odontogenic cyst (GOC) are presented and discussed in a review of 45 cases of GOC hitherto reported. Of cases with available information, 34 occurred in the mandible and 6 in the maxilla; the male:female ratio was 19:28, and the mean age was 46.7 years in males and 50.0 years in females. Six cysts recurred once after 2-8 years (mean 2 years 8 months) and 2 (5.3%) recurred twice after 2 and 5 years and after 3 and 5 years, respectively, giving a rate of recurrence of 21%. The identification of osteodentin in one of the present cases and the co-expression of cytokeratins (CK) 13, 19 and 8 strongly support the concept of odontogenic differentiation in the GOC. Careful surgical removal of the lesion succeeded by a 5-year follow-up period is recommended.

Orthokeratinized odontogenic cyst: a clinicopathological and immunocytochemical study of 15 cases

AIMS

Intraosseous jaw cysts with a solely orthokeratinized lining epithelium have been suggested to differ from the typical odontogenic keratocysts (OKC) by exhibiting a less aggressive behaviour. We report 15 cases of such cyst type under the term of 'orthokeratinized odontogenic cyst (OOC)' and compared their clinical, histological and immunocytochemical features with that of OKC.

METHODS AND RESULTS

The cysts of the present series were all solitary lesions, occurred mostly in young male patients, and showed a predilection for the posterior mandible areas. Follow-up of 14 patients, nine of whom were treated by simple enucleation, revealed no recurrence over a period of 3.5-12 years after surgery. None of the patients had any association with the naevoid basal cell carcinoma syndrome. Furthermore, histological and immunocytochemical comparison between OOC and OKC revealed marked differences in their morphology and epithelial expression. The lining epithelium of OOC lacked the typical features of OKC and appeared to show a lower proliferative activity.

CONCLUSION

These findings suggest that OOC is clinicopathologically separate from other types of odontogenic cysts and may thus constitute a distinct clinical entity.

The glandular odontogenic jaw cyst: report of a case

A case of a rare odontogenic cyst arising in the lateral periodontal membrane in the mandible in a 14 year old girl is reported. This lesion appeared to be a new entity and has been named glandular odontogenic cyst (GOC) or sialo-odontogenic cyst. Histologically the lesion was lined by mucous producing cuboidal epithelium containing several areas of thickening and numerous duct-like structures. The cyst recurred with the same histology two years postoperatively.

Glandular odontogenic cyst with hyaline bodies: an unusual dentigerous presentation

We present an unusual case of glandular odontogenic cyst (GOC) enclosing the crown of an impacted canine that developed in the anterior mandible in a 54-year-old woman. Microscopically, it contained numerous glandular structures and hyaline bodies in the epithelial lining. The present rare case is sufficiently distinctive to be considered a dentigerous variant of GOC.

Vacuolated cells and mucous metaplasia in the epithelial linings of radicular and residual cysts

The purpose of this study was to determine whether a consistent association exists between mucous cells and clear or vacuolated cells in the epithelial lining of radicular and residual cysts and to consider whether the vacuolated cells may represent a stage in the histogenesis of mucous metaplasia in these linings. Single sections from each of 154 mandibular radicular and residual cysts were stained with periodic acid-Schiff (PAS) after diastase digestion. Fifteen cases which showed mucous metaplasia were included in the study and were examined for the presence of vacuolated cells associated with the mucous cells. Mucous cells were present singly or in groups within all layers of the stratified squamous epithelial lining except the basal cell layer. In nearly all instances small to large ovoid vacuolated cells were found closely associated with the mucous cells. Occasional vacuolated cells contained sparse mucin granules or a delicate network of PAS-positive, diastase-resistant material. It is suggested that the clear cells may represent a stage in the histogenesis of mucous metaplasia.

The small dentigerous cyst. A diagnostic dilemma

The dentigerous (follicular) cyst is recognized as one of the most common lesions of the jaws. Clinical, radiographic, histologic, and prognostic characteristics are well established for medium to large pericoronal cysts that are lined by nonkeratinized stratified squamous epithelium. However, it can be difficult, if not impossible, to distinguish between a small dentigerous cyst and a large dental follicle despite the availability of both radiographic and histologic information. Epidemiologic data derived from a comparative study of 1662 dentigerous cysts and 824 dental follicles showed considerable overlap in age distribution and site predilection and were therefore of minimal use in reaching a final diagnosis. At present, it appears that identifying a cystic cavity at the time of surgery may be the only reliable way to arrive at a definitive diagnosis when radiographic and histologic features are insufficient to distinguish between a small dentigerous cyst and a large dental follicle.

Glandular odontogenic cyst: analysis of cytokeratin expression and clinicopathological features

The glandular odontogenic cyst (GOC) is a rare odontogenic cyst which is still controversial in regard to classification, terminology, and origin. The first Japanese case of GOC is reported. Immunohistochemical examination for expression of cytokeratins and epithelial membrane antigen by monoclonal antibodies suggested that the lining epithelium was of odontogenic origin with metaplastic mucus-laden cells. We have reviewed the literature and compared the clinicopathological findings of the reported case of GOC with those of botryoid odontogenic cysts (BOC). The anatomical location, age range, and sex of GOC cases were very similar to those of BOC. GOC appears to be a multiocular and mucoepidermoid variant of non-keratinizing odontogenic cysts, which also includes BOC. GOC should be separated from the other types of odontogenic cyst and central mucoepidermoid tumours of salivary gland origin.

Globulomaxillary cyst revisited

Classically, the globulomaxillary cyst was considered to be an inclusion or developmental cyst that arises from entrapped nonodontogenic epithelium in the globulomaxillary suture. Subsequently Christ disputed the existence and histogenesis of this lesion stating that the evidence indicated that facial processes per se did not exist. The development of the anterior maxilla was attributed to the merging of growth centers rather than fusion of facial processes, and hence ectodermal entrapment was ruled out. Recent embryologic studies, however, have demonstrated that Christ's view of facial development was incorrect. Fusion of facial processes does occur, and epithelium is entrapped in areas that later will lie between the maxillary lateral incisors and canines. This review argues that embryologically and histopathologically the globulomaxillary cyst should again be considered as an identifiable clinicopathologic entity.