Oral cancer and precancer in Oral Pathology and Medicine curricula of Mexican dental schools.

OBJECTIVE: To identify the teaching-learning process characteristics of Oral Pathology and Medicine (OP&M) related to oral potentially malignant disorders (OPMDs) and oral cancer (OC), in the dental schools' curricula in Mexico, to analyze the approach given to this topic worldwide, and to provide the possible solution strategies. MATERIALS AND METHODS: Questionnaires were sent to OP&M deans and professors from public Mexican Universities to explore the curriculum and academic profile of the dental schools. The recommendations gathered from a workshop with expert professors on the challenges in OPMD/OC teaching were reported. RESULTS: Twenty-two dental schools participated (22 deans, 30 professors). The most widely used strategies were clinical-case resolving (86%) and presentations (73%). Although 77.3% of the programs included maxillofacial lesions, only 40.9% contemplated OPMD/OC. Only 45% of the programs developed community activities for early OC detection. The workshop recommendations were (i) multidisciplinary approach to OPMD/OC teaching, involving OP&M professors in other dental and nondental courses; (ii) implementation of the most effective teaching techniques (currently, problem-based learning and clinical-case presentation) in OP&M curricula; (iii) education of OP&M professors on teaching-learning processes. CONCLUSIONS: These recommendations from the Mexican context, integrated with similar experiences from other countries could contribute to develop a unique, internationally acknowledged OP&M curriculum.

Fibrolipoma of the hard palate: an uncommon location. Case report / Fibrolipoma del paladar duro: una ubicación poco frecuente. Reporte de caso

Abstract Fibrolipoma, a benign soft tissue adipose tumor, is a histological variant of lipoma. Clinically, it presents as a painless slow-growing mass, indistinguishable from other benign soft tissue tumors. In the oral cavity, it is mainly encountered in the buccal mucosa. Involvement of the palate is very rare; it accounts for around 7-14% of all oral fibrolipomas. In this article, we describe a case of fibrolipoma in the hard palate of a 70-year-old female, who presented with an asymptomatic pedunculated mass, characterized by a normal-colored and smooth surface, which have been present for 20 years. The lesion was excised, and histopathological study revealed a fibrolipoma. To the best of our knowledge, only 17 cases occurring in the palate have been reported in the literature. Since fibrolipoma presents clinical similarities with other benign soft tissue neoplasms, a thorough clinical examination and histopathological analysis are essential for obtaining diagnosis.

Resumen El fibrolipoma es una neoplasia benigna de tejido adiposo, variante histológica del lipoma. Clínicamente se presenta como una tumoración de crecimiento lento, asintomática, indistinguible de otras neoplasias benignas de tejidos blandos. En cavidad oral se presenta principalmente en la mucosa yugal. El paladar es un sitio infrecuente, comprende del 7 al 14% de todos los fibrolipomas. En este reporte, describimos un caso de fibrolipoma de paladar duro en una mujer de 70 años de edad, que presentó una tumoración pediculada, asintomática, de superficie lisa, del mismo color de la mucosa adyacente, con un tiempo de evolución de 20 años. La lesión fue extirpada, y el estudio histopatológico reveló un fibrolipoma. En nuestro conocimiento, se han reportado en la literatura únicamente 17 casos de fibrolipoma de paladar. Siendo que el fibrolipoma presenta similitud clínica con otras neoplasias benignas de tejidos blandos, un examen clínico detallado, así como el estudio histopatológico son esenciales en la obtención del diagnóstico.

PD-L1 expression patterns in oral cancer as an integrated approach for further prognostic classification.

BACKGROUND: Despite the well-known role of programmed cell death ligand 1 (PD-L1) in promoting immune resistance in oral squamous cell carcinoma (OSCC), its potential utility as a prognostic biomarker is undetermined. We evaluated PD-L1 expression as predictor of survival in patients with OSCC and explored PD-L1 expression patterns. METHODS: We conducted a retrospective cohort study that assessed PD-L1 expression through immunohistochemistry in 123 surgical specimens of OSCC. A first approach evaluated tumor proportion scores (TPS) and combined proportion scores (CPS). Next, expression patterns were examined by evaluating PD-L1 localization in tumor nests, as well as the interfaces of tumor cells (TC) and immune cells (IC) in the tumor microenvironment. RESULTS: High-level PD-L1 expression determined by TPS and CPS using variable cutoffs was not associated with survival. Immunohistochemistry revealed that TC expressed PD-L1 in either patchy or diffuse patterns. The patchy pattern was an independent risk factor for overall survival. Furthermore, expression patterns in the tumor immune microenvironment showed that most cases expressed PD-L1 on both TC and IC, while PD-L1 non-expressors had the lowest overall survival. CONCLUSION: PD-L1 expression patterns in the context of localization in tumor nests and TC-IC interactions represent antitumor immune responses better than either TPS or CPS. Our suggested classification system may have important implications for the characterization of OSCC and for the use of PD-L1 as a prognostic biomarker.

Conocimiento y preparación de los odontólogos mexicanos ante la pandemia por COVID-19 / Knowledge and preparation of Mexican dentists facing the COVID-19 pandemic

Introducción: La pandemia a la que nos enfrentamos globalmente ha impactado de manera importante a la práctica odontológica, ya que, debido al uso de aerosoles, es una profesión de alto riesgo de transmisión de COVID-19. Objetivos: Describir los conocimientos generales sobre el SARS-CoV-2, recomendaciones y medidas de protección en una muestra de odontólogos mexicanos. Material y métodos: Se realizó un estudio descriptivo, transversal utilizando un instrumento de evaluación que se distribuyó en línea a instituciones públicas, privadas y asociaciones dentales mexicanas. Los resultados fueron analizados por medio de estadística descriptiva. Resultados: La encuesta fue respondida por 1,286 odontólogos, el 73.1% reportó haberse capacitado recientemente acerca del SARS-CoV-2. En su mayoría conocen sobre grupos de riesgo, transmisión, características clínicas, y recomendaciones generales. La mayoría se encuentran atendiendo exclusivamente urgencias y demuestran conocimiento acerca de los equipos de protección personal y del protocolo de atención durante la pandemia. Conclusiones: Los odontólogos mexicanos cuentan con los conocimientos sobre las generalidades del SARS-CoV-2, así como sobre los protocolos de atención y equipos de protección personal para la atención de pacientes durante la pandemia por COVID-19 (AU)

Introduction: The current pandemic that we are facing globally has had a significant impact on dental practice, due to the use of aerosols it is a profession with high risk of CoViD 19 transmission. Objective: To describe the general knowledge about SARS-CoV-2, as well as on the recommendations and personal protective equipment in a sample of Mexican dentists. Material and methods: A descriptive, transversal study was carried out through an evaluation instrument distributed on-line during 20 consecutive days to several dental professionals of private and public institutions and Mexican dental associations. Results were analyzed using descriptive statistics. Results: 1,286 Mexican dental professionals completed the survey, 73.1% indicated having received training about SARS-CoV-2 and they mostly know about the individuals at higher risk, transmission, clinical features and general recommendations. Most of the dentists are exclusively attending urgencies as pulpal pain, abscess and dental traumatisms. Knowledge regarding the use of personal protective equipment was demonstrated, as well as the protocol of care during the pandemic. Conclusions: Mexican dentists have the knowledge on the generalities of SARS-CoV-2, on care protocols and protective measures for patient care during the CoViD-19 pandemic (AU)

Nasopharyngeal Angiofibroma: A Clinical, Histopathological and Immunohistochemical Study of 42 Cases with Emphasis on Stromal Features.

Nasopharyngeal angiofibroma is a benign but aggressive tumor of unknown etiology, typically occurring in adolescent males. It is described as a rare neoplasm; however, the prevalence seems to have geographic differences. All cases referred to our head and neck clinical and pathology service were reviewed. Most of the patients presented at an advanced stage. The clinical and radiographic features are presented and discussed. Histologically, the tumor shows a highly vascular fibrous proliferation with characteristic plump, angulated and stellate cells, categorized as fibroblasts. Immunohistochemistry was performed on 42 cases to further elucidate the nature of these cells. The stromal cells expressed vimentin and factor XIIIa, the latter expressed most commonly in the giant stellate cells. Inflammation was almost exclusively present in peripheral subepithelial areas. Mast cells were abundant, even in the absence of other inflammatory cells. Lymphatics were observed principally in peripheral regions. Proliferating cells (Ki-67 reactive) were restricted to endothelial cells.

Epstein-Barr Virus in Nasopharyngeal Carcinoma of Guatemalan and Brazilian Patients.

BACKGROUND: Nasopharyngeal carcinoma (NPC) is highly associated with Epstein-Barr virus (EBV), particularly the undifferentiated nonkeratinizing subtype. Prevalence of EBV in NPC in countries such as Guatemala and Brazil has not been studied. METHODS: We analyzed 19 cases of NPC, 11 from Guatemala and 8 from Brazil, for the presence of EBV by in situ hybridization and immunohistochemistry. Additionally, 19 hyperplastic adenoids from children were analyzed for EBV by in situ hybridization, 12 from Guatemala and 7 from Brazil. RESULTS: All the NPC cases from Guatemala and 5 from Brazil were of the undifferentiated nonkeratinizing type. EBV-negative cases comprised 2 keratinizing NPC and 1 differentiated nonkeratinizing NPC. All undifferentiated nonkeratinizing NPC from both samples showed intense positivity for EBER, while LMP-1 only focally and scarcely expressed. EBER was positive in 75% and 43% of the adenoids from Guatemala and Brazil, respectively. CONCLUSIONS: All undifferentiated nonkeratinizing NPC irrespective of origin from Guatemala or Brazil were highly associated with EBV.

Malignant peripheral nerve sheath tumor of the lower labial mucosa: case report and literature review.

Malignant peripheral nerve sheath tumor (MPNST) is an uncommon soft tissue sarcoma with a predilection for the extremities and trunk of adults, rarely occurring in the oral cavity. To date, 10 cases of MPNSTs affecting the lower labial mucosa have been reported in the English language literature. We describe an additional case of MPNST in the lower labial mucosa of a 67-year-old male patient, who exhibited a painful swelling with a history of 4 months of evolution. Microscopic examination showed dense plexiform fascicles of spindle cells with wavy atypical nuclei. Mitotic figures and nuclear pleomorphism were evident. Immunohistochemical analysis of tumor cells revealed positivity for S-100 protein, CD56, CD34, and neuron-specific enolase but was negative for neurofilament protein, glut-1, claudin-1, desmin, and smooth muscle actin. Ki-67 labeling was 20%. The final diagnosis was MPNST. The lesion was surgically removed with wide margins, with no signs of recurrence after 4 years of follow-up.

Primary intraosseous squamous cell carcinoma arising in an odontogenic keratocyst previously treated with marsupialization: case report and immunohistochemical study.

A rare case of primary intraosseous squamous cell carcinoma arising in an odontogenic keratocyst (OKC) is presented here, with the clinical and histologic features of the first biopsy showing characteristics of OKC and the second biopsy disclosing a squamous cell carcinoma. Immunoprofile of this case was compared with five cases of classical OKC by using cytokeratins CK5, CK14, and CK19, CD138, p63, Ki-67, p53, and bcl-2. Classic OKCs showed expected positivity, mainly in the basal and/or suprabasal layers with most antibodies, except for p53, which was negative, whereas the present case showed irregular positivity in all layers, indicating that this can be useful for differential diagnosis and suggesting a possible role in malignant transformation into primary intraosseous squamous cell carcinoma. In conclusion, immunohistochemical differences between the first biopsy of the present case and classic OKC suggest that immunohistochemistry can be helpful in cases with areas of subtle initial malignant transformation.