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BACKGROUND: Oral Pathology curriculum is taught as didactic lectures which promotes rote learning. This study intends to introduce and assess the impact of Case based Learning in student\'s performance and to obtain the perception of students towards it.
METHODS: This cross-sectional study was conducted from March 2021 to January 2022 among dental undergraduate students (N=25) of Gandaki Medical College, Pokhara. The syllabus of Potentially Malignant Oral Lesions and Oral Cancer were covered for BDS third year students by didactic lectures, followed by Case Based Learning sessions (session I- Oral Leukoplakia, session II- Oral Squamous Cell Carcinoma). A pre-test and post-test, containing Multiple Choice questions relevant to the topics, were administered before and after the interventions. Students\' perceptions were collected using feedback questionnaire. The scores obtained in the pre and post-test were compared by Wilcoxon pair test and Mann Whitney U test. The level of significance was set at p <0.05.
RESULTS: Twenty and 21 students participated in session I and II respectively, and all (100%) of them felt that the case scenarios made the subject more interesting, and 19 (90.5%) students felt more such sessions should be added and be used along with lectures. Post test score after case-based learning was significantly higher (For Oral Leukoplakia p=0.028, for Oral Squamous Cell Carcinoma p<0.001) in comparison to didactic lectures.
CONCLUSIONS: As case-based learning was positively perceived and preferred along with lectures, an attempt to incorporate it along with lectures in clinically important topics should be made.

Oral squamous cell carcinoma (OSCC) is one of the most common malignant tumours with increasing incidence, and oral leukoplakia (OLK) has a strong tendency to undergo malignant transformation. The oral microbiota may influence oral cancer progression, but the salivary bacterial composition and functional changes in OSCC and OLK have not been comprehensively elucidated. Therefore, we compared salivary bacteria in OLK and OSCC patients with healthy controls (HC).
Metagenomic sequencing was used to compare the bacterial composition and functional changes of 18 OSCC patients, 21 OLK patients and 21 HC. Spearman correlation was used to identify possible associations between functions and bacteria.
Gemella was the most differentially enriched genus in OSCC. At the species level, Streptococcus sp. NPS 308, Streptococcus agalactiae, Gemella haemolysans and Gemella morbillorum were slightly increased in OLK and OSCC. Kyoto Encyclopedia of Genes and Genomes (KEGG) results showed that OSCC was mainly associated with metabolism functions, including lipid metabolism, carbohydrate metabolism and glycan biosynthesis and metabolism. The synthesis and degradation of ketone bodies, cysteine and methionine metabolism and glycerolipid metabolism differed significantly among the three groups, and were highest in OSCC and lowest in HC. And G. haemolysans was significantly associated with these selected metabolic pathways.
Metagenomic analysis revealed significant differences in the salivary microbiota among OSCC, OLK and HC. Thus, salivary microbiota composition and functional changes may be associated with OSCC progression. Metabolism of nonessential amino acids such as cysteine and methionine in bacteria may play an important role in oral oncogenesis, and more studies of the mechanism between metabolisms of bacteria and oral oncogenesis are needed in the future.

Proliferative verrucous leukoplakia (PVL) is a distinct progressive and multi-focal form of oral leukoplakia, not associated with the traditional risk factors (ie, tobacco and alcohol consumption). The incidence of oral squamous cell carcinoma in PVL patients is high. Here, we describe the case of a patient affected by PVL, who developed two metachronous oral verrucous carcinomas at different sites of the oral mucosa. Owing to the high risk of multiple oral squamous cell carcinoma, periodical clinical and histopathological follow-up is mandatory and should continue lifelong.

BACKGROUND: Proliferative verrucous leukoplakia (PVL) is a multifocal, slowly evolving lesion that resists all types of treatment and has a high propensity for malignant transformation into oral squamous cell carcinoma. Lack of awareness and acquaintance with white lesions of the oral cavity makes it difficult to diagnose. Besides being rare, PVL significantly aggressive, so clinicians need to be aware of it carefully. Therefore, it is recommended to have the earliest possible diagnosis and total excision of this lesion. We report this case to present typical clinical and histologic features of PVL so a For the purpose of sensitizing clinician.
METHODS: A 61-year-old female came to the clinic concerning of recurring painless, white patch on the tongue 2 months ago, associated with oropharyngeal dryness.
METHODS: This case satisfies these major and minor criteria to diagnosed PVL.
METHODS: An excisional biopsy of the lesion was done to check for the presence of dysplasia, as lesions were persisting. Hemostasis was achieved with single interrupted sutures.
RESULTS: no recurrence has been observed since excisional 1 year follow-up.
CONCLUSIONS: The key feature is early detection, precisely in cases of PVL it is critical for better treatment outcomes, lifesaving, quality-of-life enhancement. To detect and treat any potential pathologies, clinicians should meticulously examine the oral cavity and patients have to be aware and informed of the importance of regular screenings. This lesion is resistant to the presently available treatment modalities; therefore, total excision with free surgical margins is critical combined with a lifelong follow-up.

In April 2020, a state of emergency was declared because of the pandemic, and the public was instructed to refrain from leaving their homes. Consequently, this stirred up anxiety about visiting medical institutions. Here, we describe a case of tongue carcinoma that developed from an oral precancerous lesion into a malignant transformation owing to the effects of refraining from medical examinations caused by the pandemic. The patient was a 62-year-old woman. In March 2020, the patient became aware of a mass at the tongue\'s margin and was referred to our department. An excisional biopsy was performed, and a diagnosis of inflammatory change was made. The following month, a white ulcerative lesion was found, and another excisional biopsy was performed; therefore, a diagnosis of left tongue leukoplakia without epithelial dysplasia was made. The patient was scheduled for surgery; however, refused treatment and consultation because of the pandemic. In September 2021, the patient revisited our department on her own volition because an ulcerative lesion with indistinct borders and induration was found at the left lingual margin. Upon close examination, a diagnosis of left tongue squamous cell carcinoma(cT2N2bM0, Stage ⅣA)was made. In October 2021, radical tumor resection and reconstruction were performed. After 8 months postoperatively, the patient is currently well.

BACKGROUND: Oral leukoplakia and oral submucous fibrosis are potentially malignant disorders of the oral cavity, with high rates of recurrence and malignant transformation. Notably, the malignant transformation rate of oral leukoplakia with concomitant oral submucous fibrosis is significantly higher than that of oral submucous fibrosis or oral leukoplakia alone. However, the management of these conditions is not well defined. Photodynamic therapy is a minimally invasive treatment modality that effectively targets oral potentially malignant disorders, such as oral leukoplakia, erythroleucoplakia, and verrucous hyperplasia, with the advantages of being repeatable and leaving no scarring.
METHODS: We report the case of a 42-year-old man with concomitant oral leukoplakia and oral submucous fibrosis almost involving the entire right buccal mucosa, who underwent six sessions of topical 5-aminolevulinic acid-mediated photodynamic therapy.
RESULTS: Photodynamic therapy successfully eradicated whitish plaques and improved mouth opening without any adverse effects. Although photodynamic therapy failed to completely reverse the pathological changes, grading of epithelial dysplasia did not progress and clinical recurrence was not found during the 10-month follow-up.
CONCLUSIONS: In conclusion, topical 5-aminolevulinic acid-mediated photodynamic therapy appears safe and has excellent clinical efficacy against oral leukoplakia-concomitant oral submucous fibrosis, but long-term follow-up is necessary.

Oral leukoplakia (OL) and oral submucosal fibrosis (OSMF) are precancerous conditions with common etiologies but with different risks for oral cancer (OC) progression. In rare cases, both conditions occur in the same patient and provide an opportunity for understanding the common and distinctive variants upon exposure of genetically identical normal cells to the same carcinogen(s). We performed exome sequencing of a patient with OL (hyperplasia, but no dysplasia) and OSMF (grade II) in the opposite cheeks using blood DNA as the reference genome. The overall somatic variant burden was higher in OSMF than OL, but opposite in the case of copy number alterations. OL-specific variants were enriched in genes associated with DNA repair, cell division/cell cycle checkpoint pathways, whereas in OSMF, extracellular matrix-receptor interaction was mainly affected. The proportions of variants in cancer driver genes and cancer driver mutations were similar in both cases indicating no difference in the potential risk associated with the two conditions at the stages sampled. Future studies on rare cases similar to the one described in this report will help in understanding the molecular basis of differences associated with OL and OSMF and shared processes accompanying OC progression.

Non-homogeneous oral verrucous/granular leukoplakia is a potentially malignant disorder with a higher malignant transformation rate than homogeneous leukoplakia. Surgical resection is commonly performed since the disease is often malignant and refractory. However, surgical intervention is painful and heavily impairs the patients\' quality of life. Photodynamic therapy is minimally invasive, can be administered repeatedly, and is widely used to treat potentially malignant disorders and cancers. We report a case of oral verrucous/granular leukoplakia with extensive lesions in a 58-year-old man. Histopathological examination showed moderate-to-severe dysplasia and a tendency of malignant transformation in the focal area. At this stage, the patient was recommended for surgery by the oncology department. With the patient\'s consent, photodynamic therapy was performed at our department while he awaited the surgery. In the absence of any auxiliary measures, eight treatments with 5-aminolevulinic acid-mediated photodynamic therapy achieved favorable results, and there no recurrence was observed after 7 months of follow-up. This result suggests that photodynamic therapy should be considered when treating potentially malignant disorders such as oral verrucous/granular leukoplakia, or as pre-treatment before surgical resection.