Ameloblastoma with mucous cells: A clinicopathological, BRAF mutation, and MAML2 rearrangement study.

OBJECTIVES: To investigate the clinicopathological features, BRAF V600E mutation, and MAML2 rearrangement of ameloblastoma with mucous cell differentiation. MATERIALS AND METHODS: Five cases of ameloblastoma with mucous cell differentiation were retrospectively studied. Clinicopathological features, BRAF V600E mutation, and MAML2 rearrangement were analyzed. Follow-up information was available for all cases. RESULTS: Of five cases, two cases were male and three were female, aged 18-55 years. Four cases were located in the mandible and one case in the maxilla. Histologically, four of the five cases (80%) presented with cystic features and three of the five cases (60%) with varying degrees of squamous metaplasia. The mucous cells were located in the epithelial islands or the luminal aspect of the cystic cavities. The BRAF V600E mutation was found in three of five cases (60%). All the cases showed no MAML2 rearrangement. Two cases were recurrent lesions, and one case had a local recurrence during the follow-up. CONCLUSIONS: Ameloblastoma with mucous cell differentiation is closely related to the cystic features, squamous metaplasia, and shows a high prevalence of BRAF V600E mutation. The absence of MAML2 rearrangement reveals that ameloblastoma with mucous cell differentiation and central mucoepidermoid carcinoma (MEC) are two distinct tumor entities.

[Clincopathological analysis of 171 patients with osteochondroma and malignant transformation in maxillofacial bone].

PURPOSE: To investigate the clinical and pathological features of osteochondroma in maxillofacial region, and to summarize the clinicopathological features of rare osteochondroma malignant transformation in order to provide clinical guidance. METHODS: From January 2018 to September 2023, a total of 171 patients with osteochondroma were retrospectively collected in Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine. Their preoperative CT and clinicopathological features were analyzed. RESULTS: Of the 171 patients with osteochondroma in maxillofacial bone, 66%（113/171） were females and 34% were male. Their age ranged from 11-76 with an average age was 44 years old. Of the 171 cases, 95.3%（163/171）in mandible condyle, 4%(7/171) in mandible processus coronoideus, and 0.5%（1/171） in zygomatic arch. The imaging findings showed that the thickness of cartilaginous cap was less than 1 cm in 98%（159/161） cases with condyle lesions. Only 2 cases(2/171, 1.1%) had malignant transformation. One was diagnosed with secondary chondrosarcoma, another developed low-grade osteosarcoma. CONCLUSIONS: Osteochondroma in maxillofacial region mostly occurs in females, and most commonly located in condylar process, with a malignant change rate of 1.1%, which is similar to that of other parts of the body. Imaging findings have important guiding significance for the diagnosis of osteochondroma malignant change.

Melanotic Neuroectodermal Tumor of Infancy: A Clinicopathological and BRAF V600E Mutation Study of 11 Cases.

PURPOSE: To investigate the clinicopathological features and BRAF V600E mutation of melanotic neuroectodermal tumor of infancy (MNTI). MATERIALS AND METHODS: Eleven cases of MNTI diagnosed at the Department of Oral Pathology were collected. Clinicopathological characteristics were obtained from the medical records. Immunostaining was performed by immunohistochemistry (IHC). Amplification-Refractory Mutation System-qPCR (ARMS-qPCR) and Sanger Sequencing were used to detect BRAF V600E mutation. RESULTS: Of the 11 cases, 3 cases were female and 8 cases were male. The mean age of the first symptoms was 3.2 months (range: 1 to 6 months). Ten cases (90.9%) located in maxilla but only one (9.1%) in mandible. Most of the cases demonstrated well-defined mass with lytic bone destruction and tooth germ affecting radiologically. Histologically, MNTI was consisted of large polygonal melanin-producing epithelioid cells and small round neuroblast-like cells which arranged in irregular alveolar, tubuloglandular and fissured architecture. The epithelioid cells expressed Vim, Pan-CK, NSE and HMB45, while the smalls cells expressed Syn, NSE and scattered Vim. Most cases showed low Ki-67 index (range: <1% to 50%). None of the MNTI cases showed BRAF V600E mutation. Most cases were treated with enucleation (45.4%) or curettage (36.4%). Among the 11 cases, 6 cases had follow-up information, and 2 cases had recurrence lesions after surgery. CONCLUSION: MNTI, an extremely rare tumor, mainly affects male infants with strong preference for maxilla. Distinct histopathological features and immunohistochemical profile are helpful to distinguish from other melanin-containing tumors and small round cell tumors. No BRAF V600E mutation in MNTI is detected in the present study and needs further investigations. The factors that contribute to the local recurrence of MNTI are controversial, but the close follow-up for the patients is recommended.

Primary pseudomyogenic hemangioendothelioma of right maxilla: a case with immunohistochemistry and FOSB rearrangement study.

OBJECTIVE: Primary pseudomyogenic hemangioendothelioma (PMH) of bone is an extremely rare vascular neoplasm. We present here a case of primary PMH occurring in the maxilla. STUDY DESIGN: A 34-year-old man was referred to our hospital for treatment because of possible recurrence after surgery and chemotherapy of a right maxillary malignant tumor. Morphologic features, immunophenotypes, and FOSB gene rearrangement status of the surgically sectioned sample were assessed by hematoxylin-eosin staining, immunohistochemistry, and fluorescence in situ hybridization, respectively. RESULTS: Morphologically, the tumor cells were arranged in a loose fascicular and sheet-like manner, with a large number of reactive woven bones forming. The most striking feature was the presence of epithelioid cells with abundant brightly eosinophilic cytoplasm, which resembled the rhabdomyoblast in appearance. The tumor was diffusely positive for AE1/AE3, CD31, erythroblast transformation-specific transcription factor, and Friend leukemia integration 1; negative for CD34, CAM5.2, epithelial membrane antigen, and desmin; and had retained expression of integrase interactor 1. The tumor harbored FOSB rearrangement. No distant metastasis was found during the follow-up period (18 months). CONCLUSIONS: To the best of our knowledge, this case represents the first report of PMH arising in the maxilla. The distinct morphologic features, immunophenotypes, and FOSB rearrangement could help achieve precise diagnosis and prevent misdiagnosis of mimics with overlapping features.

[Construction of clinical practice system of oral pathology for long-term program students in stomatology].

PURPOSE: To construct clinical practice system, making up for the shortcomings in the instructional framework of oral histology and pathology, promoting the integration of theory and clinical practice, and enhancing teaching quality of long-term students of stomatology. METHODS: Laying down clinical practice plans and formulating technical operation criteria for pathological experiments, constructing a complete database and training high-level teachers, and evaluating through the following three aspects: practice assessment, teacher-student symposium and questionnaire survey. RESULTS: After completing the clinical practice, the students got the average score of 89.37. In questionnaire survey, the students generally expressed that they had a better understanding of the specialized characteristics and routine skills of the speciality, and improved their practical ability, thus stimulating their interest in self-directed learning. CONCLUSIONS: The construction and practice of clinical practice system of oral histology and pathology can effectively improve the educational objectives and teaching quality of this discipline, which will play a positive role in scientific research and future medical work of long-term students majoring in stomatology.

[Improving the teaching quality by multiple tools and technology in oral histopathology experimental course].

PURPOSES: Oral histopathology is a course which needs to be combined with theory and practice closely. Experimental course plays an important role in teaching oral histopathology. Here, we aim to explore a series of effective measures to improve the teaching quality of experimental course and tried to train observation, thinking, analysis and problem solving skills of dental students. METHODS: We re-edited and updated the experimental textbook "guidelines of experimental course of oral histopathology", and published the reference book for experimental course--"color pocket atlas of oral histopathology: experiment and diadactic teaching". The number of clinicopathological cases for presentation and class discussion was increased, and high-quality teaching slides were added and replaced the poor-quality or worn out slides. We established a variety of teaching methods based on the internet, which provided an environment of self-directed learning for dental students. Instead of simple slice-reading examination, a new evaluation system based on computer was established. RESULTS: The questionnaire survey showed that the students spoke positively on the teaching reform for experimental course. They thought that the reform played a significant role in enriching the teaching content, motivating learning interest and promoting self-study. Compared with traditional examination, computer-based examination showed a great advantage on mastering professional knowledge systematically and comprehensively. CONCLUSIONS: The measures adopted in our teaching reform not only effectively improve the teaching quality of experimental course of oral histopathology, but also help the students to have a clear, logical thinking when facing complicated diseases and have the ability to apply theoretical knowledge into clinical practice.

[Application of diversified teaching methods to improve the teaching effects in the course of oral histology and pathology].

Oral histology and pathology is one of the most important courses in stomatological education which works as a bridge between basic medical courses and clinical courses of oral science. The knowledge of oral histopathology may help the students to correctly understand the histogenesis and development of oral diseases and provide the information for correct treatment and prevention. In order to make the students grasp the necessary basic theories, increase the interest in learning, and improve the teaching effect, we explored a diversified teaching system which included diverse teaching modes, online courses and courseware construction. The application of this system offered the interaction between students and teachers and combination of classes with the internet, and made the boring pathological knowledge be associated with clinical practice. These diversified teaching methods had been used in practice and obtained good teaching results.

Multiple idiopathic cervical root resorptions: report of one case with 8 teeth involved successively.

Multiple idiopathic cervical root resorptions is a rare condition which is usually detected as an incidental radiographic finding. It involves more than 3 teeth in the same patient and the etiology remains elusive. Diagnosis and treatment of the defect is still challenging. The present report describes a case with progressive multiple external cervical resorption involving 8 teeth, including the history, clinical and radiographic findings. Treatment included surgical intervention and restoration of the defect. A 3-month reevaluation of the case confirmed a stable, uneventful clinical recovery.