Neoplastic potential of odontogenic cysts

Odontogenic cysts and tumors are distinct entities and quite a common occurrence in the jaw bones. The lining of odontogenic cysts shows a potential for neoplastic transformation to non odontogenic malignancies like squamous cell carcinoma and mucoepidermoid carcinoma, and odontogenic tumors like ameloblastoma and adenoamatoid odontogenic tumor (AOT). AOT is a benign, epithelial odontogenic tumor, common site being the anterior maxilla. Its origin from a dentigerous cyst and in the mandible is rare. A case of an AOT arising from a dentigerous cyst associated with an impacted permanent mandibular left lateral incisor is reported.     

Adenomatoid odontogenic tumour: a case study with radiographic differential diagnostic considerations

Adenomatoid odontogenic tumours (AOT) are benign, hamartomatous odontogenic lesions that not uncommonly mimic a dentigerous cyst radiographically. Such a case as found involving an unerupted left maxillary canine in a 19-year-old Chinese female is described. The differential diagnosis of some common odontogenic cysts and neoplasms occurring in Malaysians, that may present in a dentigerous relationship to an unerupted tooth is discussed. A brief review of the radiographic literature on AOT is also included.     

Calretinin Expression in Unicystic Ameloblastoma: An Aid in Differential Diagnosis

Calretinin is a 29 kDa calcium-binding protein, which is widely expressed in the central and peripheral neural tissue. It has also been demonstrated in odontogenic epithelium during odontogenesis and in neoplastic odontogenic tissues. The lining epithelium of eight cases of unicystic ameloblastoma, six cases of dentigerous cyst, six cases of odontogenic keratocyst, reclassified as keratocystic odontogenic tumor (KCOT), and four cases of solid/multicystic ameloblastoma was examined for the expression of calretinin. No positive staining was observed in any of the dentigerous cysts and keratocystic odontogenic tumor linings. In comparison, coarse dark brown staining was seen in the stellate reticulum of solid multicystic ameloblastoma and more superficial epithelial layers of unicystic ameloblastoma. In conclusion, we have highlighted calretinin to be a specific immunohistochemical marker for neoplastic ameloblastic tissue that can be used as an important diagnostic aid in the differential diagnosis of unicystic ameloblastoma and cystic odontogenic lesions.     

Case report of a pigmented dentigerous cyst and a review of the literature on pigmented odontogenic cysts

This paper reports the first case of a dentigerous cyst containing melanin-pigment and melanocytes in the lining epithelium, and the first case of a odontogenic cyst with macroscopically visible pigmentation in the cyst wall. The patient was a 29-year-old Japanese male with a cystic lesion in the left retromolar area of the mandible. Pathologic examination revealed the lesion to be a dentigerous cyst with or without mild surface keratinization, and numerous granules of melanin-pigment were distributed in the basal cells of the epithelial lining. Furthermore, dendritic melanocytes were scattered in the basal layer. Review of the literature revealed that pigmented odontogenic cysts are uncommon, and only 11 cases have been documented; eight were odontogenic keratocyst, one was a gingival cyst, one was a botryoid odontogenic cyst, and one was a lateral periodontal cyst. The possible origin of melanocytes in odontogenic lesions is discussed.     

Central odontogenic fibroma of mandible: a case report and review of the literature

Central odontogenic fibroma is an extremely rare benign tumor, accounting for less than 0.1% of all odontogenic tumors. The most recent literature review revealed that only 69 cases have so far been reported in the English literature, and only 1 of these cases showed radiologic appearance of a dentigerous cyst and this involved impacted maxillary incisors. A case of central odontogenic fibroma occurring in the mandible of a 30-year old female with radiological appearance of a dentigerous cyst involving an impacted lower first molar, presented here, appears to be the first reported case of central odontogenic fibroma of mandible with radiological appearance of dentigerous cyst in the English-language literature.     

Frequency of odontogenic cysts and tumors: a systematic review

A systematic review of the literature from 1993 to 2011 was undertaken examining frequency data of the most common odontogenic cysts and tumors. Seven inclusion criteria were met for the paper to be incorporated. In the preliminary search 5231 papers were identified, of these 26 papers met the inclusion criteria. There were 18 297 odontogenic cysts reported. Of these there were 9982 (54.6%) radicular cysts, 3772 (20.6%) dentigerous cysts and 2145 (11.7%) keratocystic odontogenic tumors. With the reclassification of keratocystic odontogenic tumor in 2005 as an odontogenic tumor, there were 8129 odontogenic tumors reported with 3001 (36.9%) ameloblastomas, 1163 (14.3%) keratocystic odontogenic tumors, 533 (6.5%) odontogenic myxomas, 337 (4.1%) adenomatoid odontogenic tumors and 127 (1.6%) ameloblastic fibromas. This systematic review found that odontogenic cysts are 2.25 times more frequent than odontogenic tumors. The most frequent odontogenic cyst and tumor were the radicular cyst and ameloblastoma respectively.     

Cystic variant of calcifying epithelial odontogenic tumor

The calcifying epithelial odontogenic tumor is a rare benign odontogenic neoplasm of the jaw. Clinically, calcifying epithelial odontogenic tumor manifests as an intraosseous lesion (central type) in the majority of cases (95%). Extraosseous or peripheral lesions account for less than 5% of cases. Calcifying epithelial odontogenic tumor can be associated with an impacted tooth and give a radiographic simulation of dentigerous cyst. Most calcifying epithelial odontogenic tumors are solid in nature, histopathologically, and might have few cyst-like spaces within them. However, a true cystic calcifying epithelial odontogenic tumor is a rare possibility. We describe a case of a true cystic variant of calcifying epithelial odontogenic tumor in a 30-year-old male, which to our knowledge, is only the second reported case.     

Clinicopathological evaluation of 164 dental follicles and dentigerous cysts with emphasis on the presence of odontogenic epithelium in the connective tissue. The hypothesis of “focal ameloblastoma”

Objectives: Some ameloblastomas presumably originate from odontogenic epithelium within the connective tissue of dental follicles and dentigerous cysts. Therefore, it would seem reasonable to discuss as whether odontogenic epithelium proliferations, frankly displaying ameloblastomatous features (“focal ameloblastoma”), should be considered as an “early” ameloblastoma. Study Design: Histopathological reports from 164 dental follicles and dentigerous cysts from the Department of Oral and Maxillofacial Surgery/Oral Pathology of the VU Free University medical center in Amsterdam, The Ne-therlands, were reviewed. Histopathological slides from 39 cases reporting the presence of odontogenic epithelium within the connective tissue were re-evaluated in order to assess the possible presence of focal ameloblastomas. Results: Focal ameloblastomas were detected in one dental follicle and in two dentigerous cysts. During a follow-up period of 6, 8 and 22 years, respectively, no clinical signs of (recurrent) ameloblastoma have occurred in these patients. Conclusions: Focal ameloblastoma possibly represents the early stage of ameloblastoma development. Key words:Ameloblastoma, odontogenic epithelium, dentigerous cyst, dental follicle.     

Repair of an intrabony defect from an adenomatoid odontogenic tumor

This case report describes the occurrence and treatment of an adenomatoid odontogenic tumor (AOT) presenting as a periodontal intrabony defect on a upper lateral incisor. Following incision and flap reflection, a solid, rubbery specimen was enucleated in one piece leaving a wide moat-like intrabony defect. A bioabsorbable membrane of glycolide and lactide copolymer was sutured over the defect to maximize regeneration and the flaps then sutured over the membrane. Microscopic analysis of the biopsied specimen revealed dental hard tissue interspersed in a field of odontogenic epithelium in a glandular configuration, consistent with a diagnosis of AOT. AOT is a rare odontogenic tumor usually associated with unerupted teeth or dentigerous cysts, not periodontal defects. Clinical evaluation 6 months postoperatively revealed restoration of clinical attachment and periodontal health.     

Lectin histochemistry of cystic jaw lesions: an aid for differential diagnosis between cystic ameloblastoma and odontogenic cysts

The binding sites for Ulex europaeus agglutinin I (UEA-I), Bandeirea simplicifolia agglutinin I (BSA-I), and peanut agglutinin (PNA) were comparatively examined in the surgical materials from 41 cases of cystic and solid ameloblastomas and 42 cases of non-neoplastic odontogenic cysts including dentigerous cyst, odontogenic keratocyst, and radicular cyst. In non-neoplastic cysts, most of epithelial lining layers gave positive binding with UEA-I and BSA-I. However, no positive reactions were obtained for these two lectins in the epithelial components of ameloblastoma, except for limited UEA-I binding to markedly keratinized tumor cells in four cases. PNA binding was irregular and did not make any clear distinction between ameloblastomas and cysts. The results suggest that the lectin staining for UEA-I and BSA-I is a useful histologic aid for differential diagnosis between cystic ameloblastoma and non-neoplastic jaw cysts.     

Evaluation of collagen in connective tissue walls of odontogenic cysts –A histochemical study

J Oral Pathol Med (2011) 40 : 257–262 Background: The purpose of this study was to evaluate the nature of collagen in the connective tissue walls of odontogenic cysts, like the odontogenic keratocyst (OKC), dentigerous cyst and radicular cyst using picrosirius red stained sections. Furthermore, it was intended to assess if the capsular connective tissue can affect the nature of overlying epithelium, thus emphasizing the role of epithelial–mesenchymal interactions in biological behaviour of the cysts. Materials and method: The material for the study included 51 formalin‐fixed paraffin‐embedded tissue blocks (15 odontogenic keratocyst, 15 dentigerous cysts, 15 radicular cysts and four normal mucosa and two dental follicular tissue as controls), retrieved from the Department of Oral Pathology and Microbiology, MCODS, Manipal. Tissue blocks were sectioned at 5‐μm thickness, stained with picrosirius red stain and observed with polarization and light microscopy. Results: Few sections of OKC and dentigerous cyst exhibited greenish‐yellow birefringence in sub‐epithelial region, whereas others showed a yellowish‐orange birefringence under polarization microscopy. Most radicular cysts had yellowish‐orange to orange birefringence. Shift in colour in case OKC and dentigerous cyst was attributed to the presence of inflammation in those sections. These regions also exhibited either a change in phenotype or thickness of overlying epithelium. Conclusion: This technique can be used to study the nature of collagen fibres in odontogenic cyst walls. Further studies with an increased sample size and using various epithelial and mesenchymal markers and ssDNA antibodies should be carried out to confirm the effect of epithelial–mesenchymal interactions on the nature of epithelium of odontogenic cysts.     

Analysis of the neoplastic nature and biological potential of sporadic and nevoid basal cell carcinoma syndrome-associated keratocystic odontogenic tumor

BACKGROUND: Keratocystic odontogenic tumor (KCOT), also known as odontogenic keratocyst, is a benign cystic neoplasm, which may be associated with nevoid basal cell carcinoma syndrome (NBCCS) and if it does, will occur as multiple cystic lesions. KCOT is locally destructive despite its bland histological features. However, the neoplastic nature of KCOT is not well established. Heparanase is an endo-d-glucuronidase enzyme that specifically cleaves heparan sulfate (HS) and the increase of its level in tumors promotes invasion, angiogenesis, and metastasis. METHODS: To investigate the neoplastic character of KCOT, we studied the localization patterns of heparanase in KCOT, focusing on the differences between sporadic and NBCCS-associated KCOTs, by immunohistochemistry and in situ hybridization. To compare the expression pattern of these cysts with non-tumorous odontogenic developmental cyst, dentigerous cyst was included. RESULTS: All the odontogenic cysts showed positive immunoreaction for heparanase protein in various intensities. The expression pattern of heparanase gene corresponded to that of protein expression. Interestingly, intense gene and protein expressions were observed in KCOT associated with NBCCS compared with sporadic ones and dentigerous cyst. CONCLUSIONS: The results implied that heparanase expression may be correlated with the neoplastic properties of KCOT, particularly in NBCCS-associated cases.     

Adenomatoid odontogenic tumor arising in a dental cyst: report of unusual case

The case of an adenomatoid odontogenic tumor developing over a dentigerous cyst is reported. A 12-year-old boy was referred by his pediatric dentist to the service of Oral and Maxillofacial Surgery of the Asturias Central Hospital (Spain) for evaluation of a radiolucent image compatible with a dentigerous cyst. Microscopic examination revealed the presence of an adenomatoid odontogenic tumor located over the linear epithelium of a dentigerous cyst. Based on the literature, the clinico-pathological, diagnostic, radiological and therapeutic characteristics of the case are commented in detail.     

Spontaneous regression of bilateral dentigerous cysts: a case report

A dentigerous cyst is the most common developmental odontogenic cyst and believed to be slowly progressive in nature.This case report describes an incidental finding of spontaneous regression of bilateral dentigerous cysts associated with lower impacted third molars in a 30-year-old, fully dentate female.Together with three other similar reports, a few possible explanations are postulated and the understanding of natural history of dentigerous cysts is questioned. CLINICAL RELEVANCE: The discovery of a dentigerous cyst in a patient always warrants special attention.This article highlights the fact that surgical treatment is not the only solution for a dentigerous cyst and, in rare cases, conservative management can save the patient from having unnecessary surgery.     

Epidermal growth factor receptor in odontogenic cysts and tumors

The expression of epidermal growth factor receptor (EGFR) was investigated in 67 cases of odontogenic cysts and 35 cases of odontogenic tumors using monoclonal antibody to EGFR (Biomarker, Israel) to determine the presence and significance of this transmembrane growth factor receptor. The cystic epithelial cells of odontogenic cystic lesions (keratocyst 60%; primordial cyst 75%; radicular cyst 35%; and follicular cyst 47.4%) were positive to EGFR staining. Cytochemical characterization of EGFR in those cystic epithelium was cell membrane positive type as in the normal epithelium. No expression of EGFR was found in the odontogenic tumors. This diversity of EGFR represents no binding activity of EGF, or loss of EGFR in the tumor cell upon EGFR mediated growth in odontogenic tumors was suggested a different tumor cell growth factor status or microenvironment in cell proliferation mechanism at the cellular level in cysts and tumors of odontogenic origin.     

Dentigerous cyst: a retrospective clinicopathological analysis of 2082 dentigerous cysts in British Columbia,Canada

The aim of this research is to analyze the prevalence of dentigerous cysts (DCs) in a population-based cohort in British Columbia, Canada, and to report unusual cases associated with DC. The database of the British Columbia Oral Biopsy Service was searched from 1998 to 2007. 2082 histologically confirmed DCs from 2029 patients were retrieved and retrospectively analyzed for incidence, age, gender and ethnicity. The results show that this is a common jaw cyst with male predilection, has a peak incidence in younger adults and is more common in Caucasians. Multiple DCs, representing 2.5% of the cases, are not associated with any syndromes or systemic conditions. 0.5% DCs were associated with other cysts or tumours at the same site or the opposite side of the jaw. The authors report the first series of cases presenting clinically as bilateral DCs, but histologically as an odontogenic tumour or another type of odontogenic cyst. DCs can co-exist with other more serious conditions, such as odontogenic keratocyst or cystic ameloblastoma. This association with more significant conditions indicates the importance of histologically confirming any jaw cyst, even when it presents clinically as a classic DC.     

Adenomatoid Odontogenic Tumour Mimicking a Periapical Cyst in Pregnant Woman

Adenomatoid odontogenic tumours (AOT) are uncommon odontogenic lesions characterized histologi-cally by duct-like structures derived from the epithelial component of the lesion and can be distinctly classified into follicular, extrafollicular and extraosseous variants (Neville BW, Damm DD, Allen CM, et al. Adenomatoid Odontogenic Tumor. A Text Book for Oral and Maxillofacial Pathology, 2^nd edition, 621-3). Most of these tumours develop in the second or third decade of life and have a distinct predilection for women. The follicular variant accounts for 75% of reported cases (Curran AE, Miller EJ, Murrah VA. Adenomatoid odontogenic tumor presenting as periapical disease. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1997;84:557-60) and is associated with the crown of an impacted tooth, commonly the maxillary canine. We present a rare case of extrafollicular AOT mimicking a periapical cyst that originated in a woman in her first trimester of pregnancy and enlarged rapidly thereafter. The lesion was enucleated and sent for histopathology and immunohistochemistry, which revealed AOT with a cystic component with no dependence on oestrogen or progestrone for its growth. This case of AOT introduces us to the unique variation in its presentation and the difficulty in differentiation from periapical disease of inflammatory origin.     

Non syndromic unilateral dentigerous cyst in a 4-year-old child: A rare case report

Dentigerous cyst is the most prevalent type of odontogenic cyst and is associated with crown of an unerupted or a developing tooth and accounts more than 24% of jaw cysts. Here, we present an interesting case of dentigerous cyst in a 4-year-old boy, which developed around an unerupted maxillary first premolar. Histological examination revealed a cyst with 1-2-cell-thick epithelial lining and presence of inflammatory cells in the connective tissue.