Aims: Ameloblastic fibrosarcoma (AFS) is an aggressive odontogenic neoplasm featuring malignant mesenchymal stroma in addition to an ameloblastic epithelial component, and is hence considered to be the malignant counterpart of ameloblastic fibroma (AF). AFS is exceedingly rare, with <110 cases having been reported so far. Although BRAF mutations are recognised driver mutations in ameloblastoma, the molecular pathogenesis of AFS remains elusive.Methods and results: We herein describe seven AFSs that were analysed, for the first time, for mutations in the BRAF–NRAS pathway. The patients were four females and three males aged 23–57 years (median, 26 years). Three tumours developed after one or multiple recurrences of AF (4–20 years after initial diagnosis), two showed transition from AF‐like bland areas, and two developed de novo. All patients were treated with surgery; adjuvant chemotherapy was given to one patient. At the last follow‐up, five patients were alive and well (19–344 months). The remainder were lost to follow‐up. Histological examination showed variable sarcomatous overgrowth with varying degrees of atypia and increased mitotic activity. The epithelial component varied greatly according to the degree of sarcomatous overgrowth. Molecular testing revealed BRAF V600E mutations in five cases and NRAS p.Gln61Lys mutation in one case. One tumour was wild‐type.Conclusion: To our knowledge, this is the first study on BRAF/NRAS mutations in AFS. Given the activity of RAF and MEK inhibitors across different cancers harbouring V600E mutations, our data strongly suggest that all AFS cases should be genetically tested, and that targeted treatment approaches for this extremely rare sarcoma subtype should be clinically investigated.

Background/purpose: Periapical lesions of endodontic origin are often diagnosed based on the clinical and radiological presentations that may be different from the histological diagnoses. The purpose of this study was to assess the concordance between the clinical diagnosis of these lesions and the histopathological diagnoses and to analyze their clinical and pathological features. Biopsies of periapical lesions of endodontic origin diagnosed in the histopathology laboratory between 2006 and 2017 were retrieved from the database and used to conduct this retrospective review. Clinical data were obtained, and tissue samples were re-evaluated. The overall agreement between the clinical and histological diagnoses was tested utilizing the Cohen kappa (k). A total of 317 periapical biopsy specimens were included in this study which consisted of 137 periapical granulomas, 174 periapical cysts, and six periapical scars. Generally there was weak overall agreement between the clinical and histological diagnoses of periapical granuloma and periapical cysts (Cohen kappa, k = 0.059). The findings of this study indicate that clinical/radiographic examinations are not able to preoperatively determine whether a periapical lesion is a cyst or a granuloma and highlights the importance of developing a reliable nonsurgical diagnostic method to differentiate periapical lesions.

Background: Dental extraction can initiate a sequence of biological events that may lead to an insufficient bone volume, which can compromise implant placement. To minimize bone loss, alveolar ridge preservation procedures were developed. However, smoking has been shown to adversely affect the outcomes of the procedures. Hence, this clinical study aimed to assess the ability of platelet-rich fibrin to maintain ridge volume and its ability to generate vital bone in smokers. Methods: Eighteen current heavy smokers with a total of forty upper molars indicated for extraction and implant placement were randomly allocated to four different groups: an advanced platelet-rich fibrin group (A-PRF) (n = 10), a factor-enriched bone graft matrix covered by A-PRF group (A/S-PRF) (n = 10); a freeze-dried bone allograft covered by a crosslinked collagen membrane group (FDBA/CM) (n = 10), which served as a positive control; and a negative-control resorbable collagen plug group (RCP) (n = 10). Two consecutive high-resolution CBCT images were taken for each augmented socket to evaluate the bone volume, one at baseline and the other after six months, and four different measurements (vertical height, horizontal 1 mm H1, horizontal 3 mm, and horizontal 5 mm) were taken for each image. To evaluate the bone vitality, three bone samples were harvested for each group and were analyzed histologically using H and E staining. The results were analyzed using SPSS version 26.0 through the Wilcoxon sign rank test and Kruskal–Wallis test. Results: In terms of preserving bone volume, A/S-PRF showed no significant reduction in bone after six months, while A-PRF showed a significant loss according to two measurements (vertical and horizontal 5 mm), and the last two groups showed a significant loss in all four measurements. For vital bone formation, three groups (A-PRF, A/S-PRF, and RCP) showed the generation of only vital bone, while the fourth group (FDBA/CM) showed the generation of a mixture of vital and non-vital bone. Conclusions: Based on the outcomes of this study, PRF was able to minimize bone loss following dental extraction and generate vital bone in smokers.

Oral lichenoid mucositis (OLM) of the oral mucosa is a histological diagnosis mainly characterised by a band of inflammatory infiltrate in lamina propria and basal cell degeneration. These features describe oral lichen planus or oral lichenoid reaction. However, it could be seen in oral dysplasia. The study aimed to assess the demographics and clinicohistological characteristics of patients with OLM and their relevance to dysplastic changes in the oral mucosa. This was a cross-sectional and retrospective study of archived and electronic records of individuals with histological confirmation of OLM at King Saud University Medical City, Saudi Arabia. The descriptive and correlation assessments were used to describe the demographics and clinicohistological characteristics and their associations, respectively [p < 0.05]. The analysis included 140 records of patients with histological confirmation of OLM with a mean age of 47 (±13), and 57% (n = 81) were females. Notably, 40% of patients had at least one medical condition, mainly diabetes mellitus, 74% were asymptomatic, and 52% had lesions in the buccal mucosa. Dysplasia was seen in 18 (12%) of the 140 reviewed records. Regarding the associations between study variables, dysplastic changes were associated with the male gender [p = 0.024] and were of no significance with increased age [p = 0.594]. Moreover, having oral symptoms was associated with older age [p < 0.001], medical history of diabetes [p = 0.0132] and hypertension [p < 0.001]. The present study findings could help indicate the individuals with histologically confirmed OLM who suffer the most from the clinical disease and have an increased risk of dysplastic changes. Therefore, symptomatic management and long-term follow-up can be planned accordingly.

[This corrects the article DOI: 10.1016/j.xhgg.2020.100009.].