Central Mucoepidermoid Carcinoma Radiographically Mimicking an Odontogenic Lesion.

Central mucoepidermoid carcinoma (CMEC) is a rare pathological entity with only a few case reports in the literature. The present case reported an uncommon occurrence of CMEC mimicking an odontogenic lesion in a young patient. A 17-year-old female patient sought dental care due to a slight swelling located in the posterior region of the mandible on the left side. Radiographic exams revealed an osteolytic lesion with defined limits in relation to proximity to the pericoronal follicle of tooth #38. The clinical and radiographic diagnostic hypothesis was an odontogenic lesion. Histological sections showed the presence of a neoplasm of glandular origin, not encapsulated, with a predominantly cystic growth pattern. The neoplasm consisted of mucous, intermediate, and squamous cells. In the immunohistochemical staining, the neoplastic cells were positive for cytokeratin 7. Mucous cells were positive for PAS with diastase digestion. The final diagnosis consisted of mucoepidermoid carcinoma. The tumor was removed surgically, and the patient has shown no signs of relapse nor recurrence. In conclusion, CMEC may mimic radiographic features of various pathologies, but despite its rarity, clinicians and oral radiologists should consider CMEC as a diagnostic hypothesis for jaw lesions.

Adenomatoid odontogenic tumor: Features of ameloblastic-like epithelial cells differentiation, secretion, and the nature of tumor cells products.

BACKGROUND: This study aimed to investigate the differentiation of ameloblastic-like cells and the nature of the secreted eosinophilic materials in adenomatoid odontogenic tumors. METHODS: We studied histological and immunohistochemical characteristics of 20 cases using: cytokeratins 14 and 19, amelogenin, collagen I, laminin, vimentin, and CD34. RESULTS: Rosette cells differentiated into ameloblastic-like cells positioned face-to-face, displaying collagen I-positive material between them. Epithelial cells of the rosettes can differentiate into ameloblastic-like cells. This phenomenon probably occurs due to an induction phenomenon between these cells. The secretion of collagen I is probably a brief event. Amelogenin-positive areas were interspersed by epithelial cells in the lace-like areas, outside the rosettes and distant from the ameloblastic-like cells. CONCLUSIONS: There are at least two types of eosinophilic material in different areas within the tumor, one in the rosette and solid areas and another in lace-like areas. The secreted eosinophilic material in the rosettes and solid areas is probably a product of well-differentiated ameloblastic-like cells. It is positive for collagen I and negative for amelogenin, whereas some eosinophilic materials in the lace-like areas are positive for amelogenin. We hypothesize that the latter eosinophilic material could be a product of odontogenic cuboidal epithelial or intermediate stratum-like epithelial cells.

Secretory carcinoma of the salivary gland is rich in lactoferrin: a possible lactational-like differentiation?

PURPOSE: It has been hypothesised that secretory carcinoma of the salivary gland (SCsg) might have a lactational-like differentiation. Therefore, we aimed to assess the immunoexpression of breast hormonal receptors and milk-related proteins in cases of SCsg and other salivary gland tumours with prominent secretory activity. METHODS: Immunohistochemistry against prolactin and growth hormone receptors, lactoferrin, human milk fat globule 1, MUC 1 and MUC4 was performed in twelve cases of SCsg and 47 other salivary gland tumours. RESULTS: Most cases of SCsg were negative for prolactin and growth hormone receptors. All cases of SCsg showed enhanced membranous-cytoplasmic staining for human milk fat globule 1, a pattern seen in other tumour groups. Only SCsg showed widespread strong staining for lactoferrin, concomitantly in the cell compartment and secretion. The other positive tumour types exhibited restricted staining. MUC1 and MUC4 showed no distinct pattern of expression. CONCLUSION: Although SCsg failed to demonstrate a complete lactational-like differentiation, lactoferrin showed a distinctive expression pattern in SCsg compared to other tumour types, which makes it a good marker to help in its differential diagnosis.

No NFATC2 fusion in simple bone cyst of the jaw.

AIMS: Simple Bone Cysts (SBCs) predominantly occur in long bones and 59% harbour NFATC2 rearrangements. Jaw SBC is rare and was previously referred to as traumatic bone cyst. It can rarely occur in association with cemento-osseous dysplasia (COD). To determine whether jaw SBCs represent the same entity as SBC of the long bones, or if they have a different molecular signature, we collected 48 jaw SBC cases of 47 patients to assess NFATC2 rearrangement. METHODS AND RESULTS: Out of the 48 cases, 36 could be used for fluorescence in-situ hybridization (FISH), of which nine (two of which associated with COD) were successful using an NFATC2 split probe. The remaining cases failed to show adequate FISH signals. All nine cases lacked NFATC2 rearrangement and five of these showed no detectable gene fusions using Archer FusionPlex. CONCLUSION: In our study, NFATC2 rearrangement is absent in solitary jaw SBC (n = 7) and COD-associated SBC (n = 2). Our findings suggest that SBC presenting in the jaw is molecularly different from SBC in long bones. Future molecular studies may confirm the absence of clonal molecular aberrations in SBC of the jaw which would support a non-neoplastic, reactive origin.

Oral epithelial dysplasia grading: Comparing the binary system to the traditional 3-tier system, an actuarial study with malignant transformation as outcome.

BACKGROUND: Establishing the risk of malignant transformation (MT) in oral leukoplakia is usually based on grading oral epithelial dysplasia (OED) on biopsy tissue, for which two systems are proposed: a 3-tier and a binary system. Only very few actuarial studies have tested the accuracy of such methods in predicting MT, especially for the binary system. This study aimed to assess the accuracy of the two grading systems in predicting MT in a cohort of oral leukoplakia (OL) from Brazil, with follow-up data. METHODS: The sample comprised 878 individuals diagnosed with OL from 2005 to 2018. Follow-up data were obtained both locally and from the regional cancer registry. All lesions were graded using both the 3-tier and the binary systems. Kaplan-Meier curves (Log-rank Mantel-Cox) were used to assess risk and kappa to assess interobserver agreement. RESULTS: Thirty-five individuals underwent MT (4%). Both systems demonstrated prognostic value, though the 3-tier system proved superior, with OR 9.23 (3.42-23.69), PPV 0.152, NPV 0.98, compared to binary OR 3.49 (1.79-6.79), PPV 0.079, NPV 0.976. Interobserver agreement was also superior in the 3-tier system (0.47, p < 0.05) compared to the binary system (0.139, p = 0.39). Combining the two systems enhanced prognostic values (OR 14.28, PPV 0.217, NPV 0.981). CONCLUSION: The 3-tier system presented superior prognostic value to the binary system. Combining both systems to double-grade intermediate lesions might enhance risk assessment.

Effect of ozone therapy on the modulation of inflammation and on new bone formation in critical defects of rat calvaria filled with autogenous graft.

OBJECTIVE: The aim of this study was to evaluate the effect of ozone therapy on new bone formation and inflammation modulation in defects of rat calvaria filled with autogenous bone. MATERIAL AND METHODS: Critical size defects were created in the calvaria of 24 male Wistar rats. The animals were randomly divided into four groups according to the treatment: G1: clot; G2: clot and covered with xenogenic membrane; G3: particulate autogenous bone graft; G4: autogenous bone graft and application of 3 mL O2/O3 gas mixture (10 µg/ml). The defects were filled immediately after surgery with a bilateral retroauricular application, in the region immediately above the incision. After 21 days, the animals were euthanized, and the samples were processed for morphometric evaluations designed to measure both the intensity of the inflammatory infiltrate, and the presence of new bone formation in the defect. RESULTS: The results showed a lower inflammation score and higher mean of newly formed bone in the region of the defect for the group associated with ozone therapy (G4). The bone formed in the region of the defect could be observed as being more lamellar and mineralized in the case of associated ozone therapy. CONCLUSION: Ozone therapy represents a promising adjuvant therapy to accelerate tissue regeneration.

HIV-related plasmablastic lymphoma causing extensive bone destruction in the mandible.

Plasmablastic lymphoma (PBL) is a rare subtype of large B-cell lymphoma commonly associated with HIV infection. HIV-related PBL has a dismal prognosis. The aggressive clinical course of the disease may lead to the development of rapid-growing swellings, like several benign and malignant conditions. Herein, we reported the case of a 38-year-old woman with a painful swelling in the mandible initially diagnosed as an abscess derived from a tooth extraction. Intraoral examination revealed a painful swelling with reddish, white and purplish areas in the posterior region of the mandible without signs of infection. Imaging exams showed an extensive bone destruction in the left mandibular body. Histopathological examination revealed a high proliferation of plasmacytoid cells with nuclear hyperchromatism. Tumor cells were negative for CD20, and positive for Ki-67, CD138, IgG and lambda chain. The diagnosis of oral PBL was defined and serological test showed positivity for HIV. Eight months after starting treatment, the patient died due to complications of cancer treatment. Lymphoproliferative malignancies related to HIV infection should be included in the differential diagnosis of rapid-growing swellings in the oral cavity.

Conceptual changes in ameloblastoma: Suggested re-classification of a "veteran" tumor.

OBJECTIVES: The merging of ameloblastoma (AM) with mural unicystic ameloblastoma (UAM-M) was suggested by the 2017 WHO based on similar treatment needs. In an international multicenter study, we investigated the characteristics of their merged product (merged-AM) and raised the possibility of unifying AM and UAM (total-AM). MATERIALS AND METHODS: AM and UAM (luminal/intraluminal/mural), separate and combined, were analyzed for demographic/clinical/radiological features. ANOVA and chi-square tests were followed by univariate and multivariate analyses, and significance was set at p < .05. RESULTS: The patients' mean age was 39.6 ± 20.3 years in merged-AM (147 AM, 76 UAM-M), 45.1 ± 19.4 years in AM (p = .009). Merged-AM comprised 51.3% multilocular/48.7% unilocular tumors, AM comprised 72.5%/27.5%, respectively (p < .001). Merged-AM was associated with impacted teeth in 30.8%, AM in 18% (p = .023). The probability of merged-AM for multilocularity increased by 2.4% per year of age (95%CI 0.6-4.2, p = .009). Association with impacted teeth decreased by 7.9% per year of age (95%CI 1.9-14.39, p = .009). Merged-AM did not differ from total-AM (p > .05). CONCLUSIONS: Merged-AM partially differed from AM, but differences appeared to diminish in an age/time-wise manner. Merged-AM and total-AM were nearly indistinguishable. Therefore, AM and UAM may be considered a continuous spectrum of one type of tumor, further necessitating revision of the treatment approaches.

Primary Intraosseous Synovial Sarcoma in the Mandible.

Synovial sarcoma (SS) is a rare malignant mesenchymal tumor that mainly occurs in body extremities, being uncommon in the head and neck region. In the present study, we described a case of primary intraosseous SS arising in the mandible of a 22-year-old young male. The patient reported a painful swelling on the left side of the mandible for the last 7 months. Imaging exams showed the presence of an expansive and multilocular radiolucent lesion, extending from the left condyle to the mandibular body. The clinic diagnostic hypotheses were ameloblastoma or malignant neoplasm. Histologically, the lesion was characterized by a proliferation of spindle cells exhibiting vesicular nuclei and evident nucleolus. Neoplastic cells were positive for AE1/AE3, cytokeratin 7, vimentin, CD-99, and TLE-1 and negative for CD-34, S-100, SMA, and HHF-35. A combination of clinical, histologic, and immunohistochemical characteristics supported the diagnosis of SS. The patient was referred for treatment, and preoperative exams did not reveal any other tumor foci in the body of the patient. The final diagnosis was of a primary intraosseous SS of the mandible.

Uncommon Pigmented Carcinoma In Situ: Case Report and Brief Review.

Pigmented lesions of the oral mucosa encompass several benign and malignant conditions that may be a matter of concern under both clinical and histopathological views. We reported a case of a 62-year-old woman, presenting with an asymptomatic, deeply pigmented lesion on the soft palate. On examination, it appeared asymmetrical, with irregular borders and an area of ulceration. A biopsy, taken to rule out melanoma, revealed a pigmented carcinoma in situ. Throughout the tumor thickness, numerous interspersed melanocytes were found that did not extend to neighboring epithelium. These were large, richly dendritic, and presented abundance of melanin granules and small nuclei. Mild melanin incontinence was found. Scanty transfer of pigment to dysplastic epithelial cells was found through Fontana Masson staining. On immunohistochemical analyses, there were pancytokeratin-stained tumor epithelial cells; increased cell proliferation throughout the entire thickness of the tumor was emphasized by Ki-67 immunomarking. P16 was negative. The dendritic cells were selectively stained for S-100, HMB45 and Melan A. Wide spectrum in situ hybridization for human papillomavirus (HPV) was negative. Unfortunately, following diagnosis, the patient refused any treatment option. Pigmented squamous cell carcinoma with melanocyte colonization must be taken into account in the differential diagnosis of pigmented lesions of the oral cavity.

Diagnosis of ameloblastic fibro-odontoma: case report / Diagnóstico de fibro-odontoma ameloblástico: relato de caso

Objective: the present report describes the clinical, radiographic, and histopathological features of an ameloblastic fibro-odontoma (AFO) lesion. Case report: we report a clinical case of a 14-year-old boy with asymptomatic edema. Panoramic radiography detected a unilocular lesion with defined margins located in the posterior region of the mandible. The internal structure of the lesion presented several degrees of radiopacity with the involvement of the third molar. Cone-beam computed tomography revealed expanded buccal and lingual cortical bones, perforation of the lingual cortical bone, and displacement of the mandibular canal. AFO was suspected based on the radiographic and clinical characteristics. Total excision was performed and histologically examined, confirming the diagnosis of AFO. No recurrence occurred during a 24-month follow-up period. Final considerations: the evaluation of the clinical, radiographic, and histopathologic findings needs to be accurate for a correct diagnosis and appropriate treatment for case of AFO since the presentation is often asymptomatic.(AU)

Objetivo: o presente relato descreve as características clínicas, radiográficas e histopatológicas de uma lesão de fibro-odontoma ameloblástico (FOA). Relato de caso: relatamos o caso clínico de um menino de 14 anos com edema assintomático. A radiografia panorâmica detectou lesão unilocular com margens definidas e localizada na região posterior da mandíbula. A estrutura interna da lesão apresentava vários graus de radiopacidade com envolvimento do terceiro molar. A tomografia computadorizada de feixe cônico revelou as corticais ósseas vestibular e lingual expandidas, perfuração da cortical óssea lingual e deslocamento do canal mandibular. FOA foi a hipótese diagnóstica com base nas características radiográficas e clínicas. A excisão total foi realizada e examinada histologicamente, confirmando o diagnóstico de FOA. Nenhuma recorrência ocorreu durante um período de acompanhamento de 24 meses. Considerações finais: a avaliação das características clínicas, radiográficas e histopatológicas contribuíram para um diagnóstico correto e o tratamento adequado para o caso de FOA, uma vez que a lesão é frequentemente assintomática.(AU)

miR-22 and miR-205 Drive Tumor Aggressiveness of Mucoepidermoid Carcinomas of Salivary Glands.

OBJECTIVES: To integrate mRNA and miRNA expression profiles of mucoepidermoid carcinomas (MECs) and normal salivary gland (NSGs) tissue samples and identify potential drivers. MATERIAL AND METHODS: Gene and miRNA expression arrays were performed in 35 MECs and six NSGs. RESULTS: We found 46 differentially expressed (DE) miRNAs and 3,162 DE mRNAs. Supervised hierarchical clustering analysis of the DE transcripts revealed two clusters in both miRNA and mRNA profiles, which distinguished MEC from NSG samples. The integrative miRNA-mRNA analysis revealed a network comprising 696 negatively correlated interactions (44 miRNAs and 444 mRNAs) involving cell signaling, cell cycle, and cancer-related pathways. Increased expression levels of miR-205-5p and miR-224-5p and decreased expression levels of miR-139-3p, miR-145-3p, miR-148a-3p, miR-186-5p, miR-338-3p, miR-363-3p, and miR-4324 were significantly related to worse overall survival in MEC patients. Two overexpressed miRNAs in MEC (miR-22 and miR-205) were selected for inhibition by the CRISPR-Cas9 method. Cell viability, migration, and invasion assays were performed using an intermediate grade MEC cell line. Knockout of miR-205 reduced cell viability and enhanced ZEB2 expression, while miR-22 knockout reduced cell migration and invasion and enhanced ESR1 expression. Our results indicate a distinct transcriptomic profile of MEC compared to NSG, and the integrative analysis highlighted miRNA-mRNA interactions involving cancer-related pathways, including PTEN and PI3K/AKT. CONCLUSION: The in vitro functional studies revealed that miR-22 and miR-205 deficiencies reduced the viability, migration, and invasion of the MEC cells suggesting they are potential oncogenic drivers in MEC.

Jacob's Disease: case report / Doença de Jacob: relato de caso

ABSTRACT Jacob's disease or osteochondroma is a rare disease that presents as a pseudo-joint between the coronoid process of the mandible and the posterior surface of the zygomatic bone. The present case report is of an 11-year-old female patient with a maximum mouth opening of 2mm. When evaluating computed tomography with three-dimensional reconstruction, a mushroom-shaped increase in the coronoid process of the mandible on the left side was observed, intimately connected to the zygomatic bone (inferoposterior region of the body of the zygoma), which suggests a pseudoarticulation. Surgical removal of the tumor mass was performed under general anesthesia via intraoral access and is called coronoidectomy. Histopathological, the presence of hyaline cartilage was observed, a condition that is pathognomonic for Jacob's Disease. Jacob's disease case reports are still rare in the literature, with mushroom shape and histopathological confirmation due to the presence of hyaline cartilage.

RESUMO A Doença de Jacob ou osteocondroma é uma doença rara que se apresenta como uma pseudoarticulação entre o processo coronóide da mandíbula e a superfície posterior do osso zigomático. O presente relato de caso é de um paciente, do sexo feminino, com 11 anos de idade e com 2mm de abertura máxima de boca. Ao se avaliar exame de tomografia computadorizada com reconstrução tridimensional foi observado um aumento volumétrico no processo coronóide da mandíbula do lado esquerdo em formato de cogumelo, intimamente ligado ao osso zigomático (região inferoposterior do corpo do zigoma), o que sugere uma pseudoarticulação. A remoção cirúrgica da massa tumoral foi realizada sob anestesia geral por acesso intraoral e é denominada coronoidectomia. Histopatologicamente, observou-se presença de cartilagem hialina, condição é que patognomônica da Doença de Jacob. Ainda são raros os relatos de casos de Doença de Jacob na literatura, com formato de cogumelo e confirmação histopatológica devido à presença de cartilagem hialina.

Lipoid Proteinosis: A Rare Disease In Pediatric Dentistry.

This report describes the diagnostic process of a rare disorder in a Brazilian female child. The patient presented initially as a 7-year-old with multiple whitish submucosal nodules of a fibrous consistency in the lower lip, but with an inconclusive pathology report. When she turned 9 years of age, she presented with exacerbation of the original clinical findings, which then involved the upper lip, buccal mucosa, tongue and lingual frenulum. In addition, dermatological lesions were noted on the child's limbs and face, as well as a hoarse voice. Histopathological examination of the buccal mucosa revealed dense connective tissue with hyaline foci, which were positive with periodic acid-Schiff (PAS) staining and resistant to diastase digestion. Clinical and histopathological findings led to the diagnosis of a rare genetic disease with fewer than 300 reported cases - lipoid proteinosis. Magnetic resonance imaging revealed calcium deposits in her amygdaloid region of the brain, and nasopharyngolaryngoscopy revealed lesions in her vocal cords. The patient currently is stable and under multidisciplinary follow-up, but no treatment has been recommended to date.

KRAS mutations in brown tumor of the jaws in hyperparathyroidism.

BACKGROUND: Brown tumors are giant cell-rich lesions that result from abnormal bone metabolism in hyperparathyroidism, one of the most common endocrine disorders worldwide. Brown tumors occasionally affect the jaws and, despite well-known clinical and microscopic features, their molecular pathogenesis remains unclear. We investigated the presence of pathogenic activating mutations in TRPV4, FGFR1, and KRAS in a cohort of brown tumors since these have recently been reported in giant-cell lesions of the jaws and non-ossifying fibromas of the bones (FGFR1 and KRAS), which are histologic mimics of brown tumors. METHODS: We target sequenced 13 brown tumors of the jaws associated with primary or secondary hyperparathyroidism. As mutations in these genes are known to activate the MAPK/ERK signaling pathway, we also assessed the immunostaining of the phosphorylated form of ERK1/2 (pERK1/2) in these lesions. RESULTS: KRAS pathogenic mutations were detected in seven cases (p.G12V n = 4, p.G12D n = 1, p.G13D n = 1, p.A146T n = 1). KRAS variants of unknown significance (VUS), p.A134T and p.E37K, were also detected. All samples showed wild-type sequences for FGFR1 and TRPV4 genes. The activation of the MAPK/ERK signaling pathway was demonstrated by pERK1/2 immunohistochemical positivity of the brown tumors´ mononuclear cells. CONCLUSION: Mutations in KRAS and activation of the MAPK/ERK signaling pathway were detected in brown tumors of hyperparathyroidism of the jaws, expanding the spectrum of giant cell lesions whose molecular pathogenesis involve RAS signaling.

Lipoid proteinosis: a rare disease in pediatric dentistry

Abstract This report describes the diagnostic process of a rare disorder in a Brazilian female child. The patient presented initially as a 7-year-old with multiple whitish submucosal nodules of a fibrous consistency in the lower lip, but with an inconclusive pathology report. When she turned 9 years of age, she presented with exacerbation of the original clinical findings, which then involved the upper lip, buccal mucosa, tongue and lingual frenulum. In addition, dermatological lesions were noted on the child's limbs and face, as well as a hoarse voice. Histopathological examination of the buccal mucosa revealed dense connective tissue with hyaline foci, which were positive with periodic acid-Schiff (PAS) staining and resistant to diastase digestion. Clinical and histopathological findings led to the diagnosis of a rare genetic disease with fewer than 300 reported cases - lipoid proteinosis. Magnetic resonance imaging revealed calcium deposits in her amygdaloid region of the brain, and nasopharyngolaryngoscopy revealed lesions in her vocal cords. The patient currently is stable and under multidisciplinary follow-up, but no treatment has been recommended to date.

Resumo Este relato descreve o processo diagnóstico de uma doença rara em uma criança brasileira do sexo feminino. A paciente, inicialmente com 7 anos de idade, apresentava múltiplos nódulos submucosos esbranquiçados, de consistência fibrosa, no lábio inferior, mas com um laudo patológico inconclusivo. Quando completou 9 anos de idade, ela apresentou exacerbação dos achados clínicos originais, que envolveram o lábio superior, mucosa bucal, língua e frênulo lingual. Além disso, lesões dermatológicas foram observadas nos membros e no rosto da criança, assim como rouquidão. O exame histopatológico da mucosa bucal revelou tecido conjuntivo denso com focos hialinos, que foram positivos com coloração periódica com ácido-Schiff (PAS) e resistente à digestão da diástase. Os achados clínicos e histopatológicos levaram ao diagnóstico de uma doença genética rara com menos de 300 casos relatados - proteinose lipoide. A ressonância magnética revelou depósitos de cálcio em amígdala cerebral e a nasofaringolaringoscopia revelou lesões em cordas vocais. Atualmente, a paciente está estável e em acompanhamento multidisciplinar, mas nenhum tratamento foi recomendado até o momento.

Dental Germ Tumor: An Unusual, Cystic, Mixed Epithelial-Mesenchymal Odontogenic Tumor.

Although odontogenic lesions have been extensively described and studied, anomalous, challenging cases occasionally come to the attention of the pathologist. Here, we report the clinical and microscopic characteristics of an unusual cystic lesion of odontogenic origin. A 16-year-old male presented with swelling and pain to palpation of the right mandible as well as numbness of the right lower lip. Radiographically, the corresponding lesion was well-defined and radiolucent with internal radiopaque foci. It extended from the right first premolar posteriorly, approaching the angle of the mandible, and involved the mandibular first molar which was impacted and displaced. The second and third right mandibular molars were also impacted and displaced. The patient was treated by excisional biopsy under general anesthesia. The histopathologic examination revealed the presence of multicystic areas lined by a thin, non-keratinizing squamous epithelium that resembled the epithelial lining of a dentigerous cyst. In continuity with the cystic lining, areas of myxoid tissue reminiscent of dental papilla were observed. The myxoid tissue formed structures that were surfaced by an epithelium comprising a basal layer of ameloblast-like cells with reverse polarity of the nuclei. Above the basilar cells, additional layers of epithelial cells composed a structure resembling the enamel organ. Subjacent to the basilar ameloblast-like cells, a condensation of mesenchymal cells with polarized nuclei opposite to the ameloblast-like cells was present. These mesenchymal cells resembled odontoblasts. In addition, numerous mineralized structures amongst the odontogenic epithelial tissue were present. To date, the patient remains well and without evidence of recurrence after 36 months of follow-up.

Epithelial membrane antigen and DOG1 expression in minor salivary gland tumours.

Epithelial membrane antigen (EMA) and DOG1 are used as marker of epithelial cells, particularly the luminal cells, of salivary gland tumours. The aim of this study was to compare the EMA and DOG1 expression in tumours of minor salivary glands. Cases of pleomorphic adenoma (PA), basal cell adenoma (BCA), canalicular adenoma (CA), adenoid cystic carcinoma (ACC), polymorphous adenocarcinoma (PAC), mucoepidermoid carcinoma (MEC) and epithelial-myoepithelial carcinoma (EMC) were submitted to immunohistochemistry for EMA and DOG1. In PA and BCA, EMA and DOG1 were observed in luminal cells, while in CA the tumour cells were negative for both proteins. The EMA and DOG1 pattern expression detected in EMC was similar to that one observed in benign tumours. In ACC, both myoepithelial e epithelial expressed EMA and DOG-1. PAC tumour cells were only positive for DOG1, whereas MEC were only positive for EMA. In conclusion, EMA and DOG1 expression in benign salivary gland tumours was similar to normal salivary gland tissue and can be used as good marker of tumoral cells derived from intercalated ducts or its progenitor cells, while in malignant salivary gland tumours EMA expression is, however, better used as an indicator of aggressive behavior than a marker of luminal cells.

MiR-455-3p, miR-150 and miR-375 are aberrantly expressed in salivary gland adenoid cystic carcinoma and polymorphous adenocarcinoma.

BACKGROUND: Adenoid cystic carcinoma (AdCC) and polymorphous adenocarcinoma (PAC) are included among the most common salivary gland cancers. They share clinical and histological characteristics, making their diagnosis challenging in specific cases. MicroRNAs (miRNA) are short, non-coding RNA sequences of 19-25 nucleotides in length that are involved in post-transcriptional protein expression. They have been shown to play important roles in neoplastic and non-neoplastic processes and have been suggested as diagnostic and prognostic markers. METHODS: This study, using quantitative RT-PCR, investigated miR-150, miR-455-3p and miR-375 expression, in order to identify a possible molecular distinction between AdCC and PAC. RESULTS: miRNA-150 and miRNA-375 expression was significantly decreased in AdCC and PAC compared with salivary gland tissue controls, whilst miRNA-455-3p showed significantly increased expression in AdCC when compared to PAC, (P < 0.05). miR-150, miR-357 and miR-455-3p expression in AdCC, PAC and control was not associated with age, gender nor with anatomic site (major and minor salivary glands) (P > 0.05). CONCLUSION: MiR-455-3p could be used as a complimentary tool in the diagnosis of challenging AdCC cases.