Search

Primordial odontogenic tumour is a benign mixed neoplasm of recent description, which has histological similarities with other odontogenic tumours such as the ameloblastic fibroma. In this article, we investigate the architecture of the sub-epithelial layer of mesenchymal cells expressing the marker CD34 in primordial odontogenic tumour.Analyse the spatial patterns of CD34 expression in primordial odontogenic tumour and compare them with those in ameloblastic fibroma and the normal tooth germ by means of objective imaging approaches, to better characterise these lesions.Two cases of primordial odontogenic tumour, four cases of ameloblastic fibroma and two cases of tooth germ in cap and bell stages were used for morphological, structural and immunohistochemical analyses.CD34 expression was found in vascular endothelium of primordial odontogenic tumour, ameloblastic fibroma and tooth germ. In addition, a characteristic sub-epithelial expression was observed only in primordial odontogenic tumour, corresponding to 84%-86% of the sample boundaries. Moreover, the zone expressing CD34 corresponded with a higher cellularity, which was absent in ameloblastic fibroma and tooth germ.Image analysis of the primordial odontogenic tumour architecture revealed characteristics absent in other odontogenic tumours and tooth germs. This study provides additional information to support the idea that this neoplasm is a distinct entity from early stage AF or developing odontoma.

This systematic review aimed to incorporate published information about synchronous odontogenic tumors (SOTs) with an analysis of the demographic and clinical characteristics from the cases published in the literature. Case reports and case series of SOT were searched in PubMed, Web of Science, Scopus, and EMBASE. A descriptive statistical analysis was performed. Twenty-eight studies comprising 30 cases of SOTs were included. Considering all cases published, SOTs mostly occurred simultaneously in the maxilla and mandible (n = 19/63.3%). Lesions were bifocal in 13 (43.3% of all the 30 cases) and multifocal in 17 cases (56.7% of all the 30 cases). All SOTs available in the literature presented the same type of lesion, and two of them also involved another different SOT (n = 2/6.7% of all the 30 cases). Out of all published cases, the most frequent SOTs in the literature were odontomas (n = 10/33.3% of all the 30 cases), squamous odontogenic tumors (OTs) (n = 8/26.7% of all the 30 cases), calcifying epithelial OTs (n = 8/26.7% of all the 30 cases), and adenomatoid OTs (n = 2/6.7% of all the 30 cases). Considering all SOTs cases included, the overall recurrence was 13.3%. Inside a subgroup of the lesion, synchronous calcifying epithelial OT presented the highest (25%). Five cases (16.7% of all the 30 cases) had a previously associated syndrome, with two cases of Schimmelpenning syndrome being reported. Among published SOTs, odontomas were the most common. All SOTs available in the scientific literature showed the same type of OT and mainly affected both jaws simultaneously. Only a few of these cases were associated with a syndrome.

OBJECTIVE The aim of this study is to present and discuss the salient clinicopathological features, differential diagnosis and epithelial immunohistochemical profile of three additional cases of peripheral odontogenic keratocyst (POKC) and to present a review of the literature. POKC is a locally aggressive odontogenic lesion. The peripheral variant of the odontogenic keratocyst is rare and more frequently located in anterior gingiva. MATERIAL AND METHODS We present the clinicopathological features of 3 new cases of POKC (2 women and 1 man; age range: 14-74 years). Immunohistochemical study included CK7, CK14, CK19 and Ki-67, and a systematic review of the literature was performed in PubMed, Scopus and Web of Science databases. RESULTS All cases were located in the anterior gingiva (2 in maxilla and 1 mandible), and none corresponded to Gorlin-Goltz syndrome. High expression of CK14 was seen in all cases, with CK19 and CK7 been only focally positive. The expression of Ki-67 was located in the basal and parabasal cells in all cases. CONCLUSIONS POKC is a rare gingival lesion that seems to originate from remnants of dental lamina or from the basal cells of the gingival epithelium and present a similar histopathology as compared to intraosseous OKC.

Background Juvenile spongiotic gingival hyperplasia (JSGH) is a distinct clinicopathological entity of the buccal gingiva of young patients which has been related to several factors such as plaque formation, hormonal modifications, and viral infections; however, its true etiopathogenesis remains unsolved. Several immunohistochemical studies have demonstrated the similarity between the junctional epithelium (JE) and the hyperplasic epithelium of JSGH. The objective of this study is to analyze the clinicopathological and immunohistochemical characteristics of JSGH to explain its origin. Methods Clinicopathlogical data of 10 cases of JSGH (five men and five women) with a mean age of 13 years (range: 9 to 17 years) were collected. CK7, CK14, CK19, CD3, CD20, S100, and Ki-67 antibodies were used for comparative immunohistochemical study. Results All the lesions showed hyperplasic epithelium in its central portion, exhibiting marked spongiosis, vascular proliferation, and a chronic inflammatory infiltrate on the subepithelial connective tissue. CK19 was positive in the whole hyperplasic epithelium of JSGH and the basal layer of the marginal gingiva, while expression of CK14 was present in all epithelial layers of both the JSGH and that of the marginal gingiva. The subepithelial inflammatory infiltrate has a larger amount of CD20 positive cells. Conclusion JSGH is a reactive tumor of the gingiva that may have an odontogenic etiology, whose origin seems to be the remnants of JE.

Objective This study aimed to assess the frequency of KRAS mutation and its association with the presence of the MAPK/ERK signaling pathway proteins in adenomatoid odontogenic tumors. Study design Paraffin-embedded tissue samples from nine cases of adenomatoid odontogenic tumor were used. Genomic DNA was extracted from each sample; in one case, genetic mutations in 50 cancer-associated genes were examined by next-generation sequencing. Hotspot mutations in the RAS family were analyzed by Luminex assay using the remaining eight cases. Subsequently, immunohistochemistry for KRAS, CRAF, BRAF, EGFR, ERK, MEK, and BRAFV600E was performed. Results A KRAS G12D missense mutation was detected in the DNA sequence of the tumor cells, but it was not detected in the stromal tissue. KRAS G12V and KRAS G12R mutations were detected in two and four cases, respectively. For immunohistochemistry, all the cases were EGFR, KRAS, BRAF, CRAF positive, one case was ERK negative,and one case was MEK and ERK negative, all the other remaining cases were MEK and ERK positive. Conclusion KRAS mutation at codon 12 and the presence of MAPK/ERK pathway proteins were detected suggesting their association with tumorigenesis of adenomatoid odontogenic tumors.

Background Connective tissue autoimmune diseases (CTADs) constitute a group of conditions, including rheumatoid arthritis; systemic lupus erythematosus; mixed connective tissue disease; calcinosis, Raynaud's phenomenon, esophageal dysmotility, sclerodactyly, and telangiectasia (CREST) syndrome; scleroderma; dermatomyositis; and Sjogren syndrome. There are few studies on the alterations in filiform papillae in CTAD. Thus, the objective of this work was to determine whether there are changes in the macroscopic and dermoscopic patterns of filiform papillae. Methods This case-control study included patients who were diagnosed with CTAD. The dependent variable was the dermoscopic pattern of filiform papillae of the tongue, and the independent variables were age, gender, time of evolution, and current treatment. A photograph of the back of the tongue was taken, and subsequently, the same site was examined by dermatoscopy. The microscopic and dermoscopic patterns of filiform papillae were classified (Maeda). Results We included 50 cases and 50 controls, 94% of whom were female. The mean age was 43.96 ± 14.65 years. Of the cases with CTAD, 25% presented with a normal macroscopic pattern, versus 36% (18) with pattern II, 12% (6) with pattern III, and 20% (10) with pattern IV. The dermoscopic pattern was type I in 23 cases (46%), type II in 16 (32%), type III in 10 (20%), and type IV in one patient (2%). Conclusions We have noted alterations in filiform papillae in CTADs, which emphasizes the importance of a detailed intraoral exploration and the macroscopic and dermoscopic evaluation of the dorsum of the tongue, specifically the filiform papillae.

Background Ameloblastoma is a benign but locally aggressive odontogenic tumor, while ameloblastic carcinoma is its malignant counterpart. Angiogenesis and lymphangiogenesis in malignancies have been correlated with higher aggressiveness and poor prognosis, as well as greater expression of podoplanin by tumoral cells. Methods Immunohistochemical expression of podoplanin, CD34, and CD105 (endoglin) was evaluated in 53 ameloblastomas and three ameloblastic carcinomas; additionally, immunohistochemistry for podoplanin was also performed in 10 tooth germs. Microvessel density of blood and lymphatic vessels was calculated and compared between ameloblastomas and ameloblastic carcinomas. Immunoexpression of podoplanin by ameloblastic cells was evaluated in tooth germs, ameloblastomas, and ameloblastic carcinomas. Results Podoplanin was similarly expressed by odontogenic epithelial cells of tooth germs and ameloblastomas, while its expression was lower in ameloblastic carcinomas. There was no difference in microvessel density assessed by CD34 between ameloblastomas and ameloblastic carcinomas; nevertheless, the latter presented higher amounts of lymphatic and new formed blood vessels. Conclusions Results suggest that podoplanin does not seem to be involved in invasion mechanisms of ameloblastic carcinomas, as its expression was decreased in the malignant tumoral cells. On the other hand, the increased lymphatic microvessel density and neoangiogenesis found in ameloblastic carcinomas could be related to its aggressiveness and potential for metastasis.

Angiotensin-converting enzyme 2 (ACE2) plays a pivotal role in the regulation of blood pressure, and it is the main cell receptor for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that causes COVID-19.1,2 This article is protected by copyright. All rights reserved.

Aim: To describe the clinicopathological and immuno-histochemical features of six tumours that do notfulfil the criteria of any of the currently classifiedodontogenic tumours.Methods and results: The patients were three malesand three females, whose ages ranged from 3 yearsto 18 years (mean, 11.5 years). In all cases therewere well-defined radiolucencies associated with une-rupted teeth apparently showing a pericoronal rela-tionship. Microscopically, all tumours were composedof variably cellular loose fibrous tissue with areassimilar to dental papilla, entirely surrounded bycuboidal to columnar epithelium resembling theinternal epithelium of the enamel organ. Mesenchy-mal tissue was positive only for vimentin, and Ki67expression was very low (

Although molecular alterations are reported in different types of odontogenic tumours, their pathogenesis remains to be established. Loss of heterozygosity (LOH) studies allow the identification of minimal regions of deletions of known or putative tumour suppressor genes, the losses of which may promote neoplastic growth. The purpose of this study was to investigate LOH in a set of odontogenic mixed tumours. Tumour suppressor gene loci on 3p, 9p, 11p, 11q and 17p chromosomes were analysed in five samples of ameloblastic fibroma (AF), three samples of ameloblastic fibro-odontoma (AFO) and three samples of ameloblastic fibrosarcoma (AFS). The most frequently lost genetic loci were p53 (17p13, 62%) and CHRNB1 (17p13, 55%). LOH at the chromosome regions 3p24.3, 9p22 and 9p22-p21 was identified only in AFS. No sample showed LOH at the chromosomal loci 3p21.2 and 11q13.4. For the region 9p22-p13, LOH occurred in one sample of AFO. The fractional allelic loss (FAL) was calculated for each sample. The mean FAL of the benign lesions (i.e. AF and AFO) was 22%, whereas the mean FAL of the malignant lesions (i.e. AFS) was 74.6%. In conclusion, our results show a higher FAL in AFS compared to its benign counterparts and reveal a different pattern of LOH of tumour suppressor genes in AFS, which may regulate changes in tumour behaviour.

Oral Diseases (2011) 17, 808–812 Objective: The aim of this study was to determine the expression of fatty acid synthase (FASN) in oral nevi and melanomas, comparing the results with correspondent cutaneous lesions. Materials and Methods: Expression of FASN was evaluated by immunohistochemistry in 51 oral melanocytic lesions, including 38 intramucosal nevi and 13 primary oral melanomas, in 10 cutaneous nevi and in 14 melanomas. Results: Fatty acid synthase was strongly expressed only in melanomas, either of the oral mucosa or cutaneous. On the other hand, most oral and cutaneous nevi were negative, with a few oral cases showing focal and weak expression. Conclusion: Fatty acid synthase is expressed in malignant melanocytes, and it can be a helpful marker to distinguish oral melanomas from oral melanocytic nevi.

Background: Calcifying odontogenic cyst was described first by Gorlin et al. in 1962; since then several hundreds of cases had been reported. In 1981, Praetorius et al. proposed a widely used classification. Afterwards, several authors proposed different classifications and discussed its neoplastic potential. The 2005 WHO Classification of Odontogenic Tumours re-named this entity as calcifying cystic odontogenic tumour (CCOT) and defined the clinico-pathological features of the ghost cell odontogenic tumours, the CCOT, the dentinogenic ghost cell tumour (DGCT) and the ghost cell odontogenic carcinoma (GCOC). Methods: The aim of this paper was to review the clinical-pathological features of 122 CCOT, DGCT and GCOC cases retrieved from the files of the oral pathology laboratories from 14 institutions in Mexico, South Africa, Denmark, the USA, Brazil, Guatemala and Peru. It attempts to clarify and to group the clinico-pathological features of the analysed cases and to propose an objective, comprehensive and useful classification under the 2005 WHO classification guidelines. Results: CCOT cases were divided into four sub-types: (i) simple cystic; (ii) odontoma associated; (iii) ameloblastomatous proliferating; and (iv) CCOT associated with benign odontogenic tumours other than odontomas. DGCT was separated into a central aggressive DGCT and a peripheral non-aggressive counterpart. For GCOC, three variants were identified. The first reported cases of a recurrent peripheral CCOT and a multiple synchronous, CCOT are included. Conclusions: Our results suggest that ghost cell odontogenic tumours comprise a heterogeneous group of neoplasms which need further studies to define more precisely their biological behaviour.

Pathology Department, InstitutoNacional de Cancerologi´a, Me ´xico, D.F. Me´xicoAIM: To classify 163 ameloblastoma cases according tothe new WHO Classification of Odontogenic Tumours(2005) and analyse their clinical and microscopic features.METHODS: We studied the clinico-pathological featuresof 163 ameloblastoma cases from nine regional Latin-American institutions from Mexico and Guatemala.RESULTS: Ameloblastomas comprised 22.7% of allodontogenic tumours. The mean age was 41.4 years forsolid ameloblastoma (SA) and 26.3 years for unicysticameloblastoma (UA) (P < 0.001) and both sexes werealmost equally affected. The mandible was mainly af-fected for both UA and SA. The mean size was 6.2 cm forSA and 6.3 cm for UA cases. The recurrence rate was21.7% for SA and 12.6% for UA. UA was twice as morefrequent than the solid variant.CONCLUSIONS: In this study we found that UA wasfrequently misdiagnosed as SA; however, there are en-ough clinical and microscopic features that allow for anaccurate differentiation between both types of amelob-lastoma that should be recognized for surgical andprognostic purposes. In this study, SA was not found inpatients younger than 20 years, UA had a constantmyxoid stroma while mature connective tissue was morefrequently associated with the solid type.Oral Diseases (2007) 13, 303–307Keywords: odontogenic tumours; ameloblastoma; solid amelob-lastoma; unicystic ameloblastoma; mandibular tumours; maxillarytumours

BACKGROUND: Adenomatoid odontogenic tumour (AOT) is a benign odontogenic jaw lesion. The aim of this study was to update the biological profile of AOT. MATERIAL AND METHODS: Cases published in the literature and cases in files of co-authors were included. RESULTS: 550 new cases were retrieved, and of a total of 1082 cases analysed, 87.2% were found in the second and third decades. The M:F ratio was 1:1.9. 70.8% were of the follicular variant (extrafollicular: 26.9%, peripheral: 2.3%). 64.3% occurred in the maxilla. 60% of follicular AOTs were associated with unerupted canines. Nineteen cases of AOT (2.8%, M:F ratio was 1:1.4) were associated with embedded third molars. Twenty-two peripheral AOTs (2.3%, M:F ratio was 1:5.3) were recorded. The relative frequency (RF) of AOT ranged between 0.6% and 38.5%, revealing a considerably wider AOT/RF range than hitherto reported (2.2–7.1%). CONCLUSIONS: This updated review based on the largest number of AOT cases ever presented, confirms the distinctive, although not pathognomonic clinicopathological profile of the AOT, its worldwide occurrence, and its consistently benign behaviour.

Three cases of cartilaginous choristomas of the tongue are presented. Two lesions occurred in women of 71 and 28 years of age whose lesions were located in the middle third of the dorsum. The other lesion was found on the left lateral border in a 27-year-old man. The clinical, microscopic and immunohistochemical features are described. The lesions were easily excised with no recurrence after follow-up periods of at least 6 months. The histogenesis and the differential diagnosis are discussed, and the literature is reviewed.

Objective The aim of this study was to show the epidemiological features of 25 malignant odontogenic tumors (MOT) in Latin America. Materials and Methods We retrieved 25 cases of MOT out of 2142 odontogenic tumors, from four oral diagnostic centers in Latin America, and described the main clinical and pathological characteristics. Results A total of 19 cases were carcinomas, including eight ameloblastic carcinomas, five primary intra-osseous squamous cell carcinomas, three clear cell odontogenic carcinomas and three ghost cell odontogenic carcinomas. All six sarcomas corresponded to ameloblastic fibrosarcoma. Thirteen cases occurred in men and 12 in women, age ranged from 7 to 77 years old, with a mean of 41.4 years. The average age of patients with carcinomas and sarcomas were 48.53 and 19 years old, respectively. Conclusion As malignant odontogenic tumors are very rare, this series helps to better clarify their relative frequency, predominant subtypes, and clinical characteristics in Latin America.

Ameloblastic fibrosarcoma (AFS) is a rare malignant odontogenic tumour. To date, 60 well-documented cases have been published in the English-language literature. Two additional cases located in the posterior region of the mandible are reported. The relevant clinicopathological features of these cases, as well as those previously reported are discussed. Approximately two-thirds of AFS are malignant tumors de novo, with an average age of the affected patients being 22.9 years. This age is lower than the one observed in AFS developing from a pre-existent benign lesion (mean 33 years). Although regional and distant metastases are very infrequent, AFS is a locally aggressive lesion, with 23 (37%) of the reported cases having at least one recurrence; 12 patients (19.3%) died of the disease. Wide surgical excision with long-term follow-up remains the treatment of choice for this neoplasm.

This article describes a case of clear cell odontogenic carcinoma (CCOC) in a 55-year-old woman who presented such a tumor extending from the midline of the mandible to the right first molar. The tumor was surgically excised and has not recurred or metastasized 6 months after surgery. To date, only 33 well-documented cases have been reported (including the present case) in the English literature. Twenty-eight (84.8%) have developed in the mandible and five (15.2%) in the maxilla. Eighteen (54.5%) occurred anterior to the first molar. The vast majority have been diagnosed in patients older than 40 years (30/33), and the mean age at diagnosis is 57.4 years (range: 17-89), with a male/ female ratio:1/2. Recurrences have been described in 17 cases (51.5%) and metastasis in 10 (30.3%). Based on its morphologic, histochemical and immunophenotypic features, CCOC should be distinguished from other primary and metastasic clear cell tumors of the oral and maxillofacial regions.