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Multiple endocrine neoplasia (MEN) type 2B is the rarest and most aggressive form of MEN syndrome. MEN 2B patients manifest characteristic oral and facial features besides the neural crest cell-derived tumors, including medullary carcinoma, pheochromocytoma, mucosal neuroma, and ganglioneuromatosis of the gut. We report a case of MEN 2B diagnosed on the basis of the warning signs of mucosal neuroma and multiple neural hyperplasias in the maxillary bone resected during orthognathic surgery. A subsequent systemic examination under the pathologic diagnosis of neural lesions revealed medullary thyroid carcinoma, megacolon, thickened corneal nerves, and RET gene mutation, thus verifying the diagnosis of MEN 2B. An immunohistochemical study revealed an increased number of unmyelinated Schwann cells in the hyperplastic nerves. We suggest that intraosseous neural hyperplasia is a specific finding of the MEN 2B syndrome in addition to the known oral and facial manifestations. [ABSTRACT FROM AUTHOR]

We report a case of osseous dysplasia (OD) showing extremely rare clinical features. A 37-year-old Japanese woman was referred to our clinic complaining of a left alveolar bony swelling at an impacted canine. Radiographic examinations revealed a mixed radiopaque lesion involving the impacted left canine and also revealed an impacted left wisdom tooth with a cystic change and a clear radiopaque lesion suspected to be odontoma. All the extracted upper teeth and odontoma showed hypercementosis and the canine was fully involved in it. Histopathologically, they showed the same features and were diagnosed as OD. The findings of multiple OD from incompletely erupted teeth and odontoma in our case may well show that OD can arise from any tooth with periodontal ligaments and that focal OD can show expansive growth like the ossifying fibroma. [ABSTRACT FROM AUTHOR]

In an attempt to induce adenocarcinoma containing myoepithelial cells (MECs) in the rat submandibular gland, we injected 7,12-dimethylbenz(a)anthracene (DMBA) dissolved in acetone into the glands of rat pups at the age of 10 days. In both male and female pups, the glands, including their developing terminal secretory units, contained far greater numbers of cells positive for proliferating cell nuclear antigen (PCNA) than did adult glands. A single administration of 1% DMBA (0.05 ml/130 g b.w.) did not produce adenocarcinoma, but did induce occasional sarcomas, such as rhabdomyosarcoma and fibrosarcoma, in 2 months. Most glands regenerated with minimal scar formation. Microscopically, these glands were atypical in that they contained increased numbers of PCNA-positive cells, underdeveloped granular ducts, and striated ducts surrounded by MECs positive for alpha smooth muscle actin (αSMA). Though these features were also observed in the regenerated glands after acetone injection, the number of PCNA-positive cells was relatively high in the glands of DMBA-treated females, especially in the terminal secretory unit. The second DMBA injection at 10 weeks of age produced adenocarcinoma made up of αSMA-positive MECs and keratin 19-positive duct cells. Such MEC-associated adenocarcinoma was induced in the glands of more than half the female but not the male animals. Replacement of either of the double DMBA treatments with acetone, or DMBA treatment, single or double, of adult glands did not produce adenocarcinoma, but did produce sarcoma and squamous cell carcinoma. These results suggest that (1) at least two genetic mutations are necessary for induction of adenocarcinoma with MECs in the rat submandibular gland, (2) the mutation is efficiently introduced to pup glands whose terminal secretory units exhibit extreme proliferative activity, and (3) the second mutation is difficult to introduce in male glands, whose proliferative activity is relatively low, and/or transformed cells need some female hormone after the mutation to propagate. [ABSTRACT FROM AUTHOR]

Our recent study of developing myoepithelial cells (MECs) in rat salivary glands demonstrated that developing MECs begin to express α-smooth muscle actin (αSMA) first and, thereafter, keratin 14. Therefore, it is unlikely that duct basal cells expressing keratin 14 alone are immature or undifferentiated MECs. In this study we carried out immunohistochemistry of pleomorphic adenomas and adenoid cystic carcinomas including normal salivary glands using monoclonal antibodies to keratin 14, smooth muscle proteins and keratin 19. The smooth muscle proteins examined included αSMA, h-caldesmon and h1-calponin; h1-calponin was observed in keratinocytes and nerve fibers, indicating that the protein is not specific to smooth muscle, whereas αSMA and h-caldesmon turned out to be highly specific markers for smooth muscle cells in normal tissues. In normal glands, MECs were positive for both keratin 14 and smooth muscle proteins (αSMA and h-caldesmon). Non-MEC cells were essentially devoid of smooth muscle proteins. Non-MEC duct basal cells expressed keratin 14 with or without keratin 19, and luminal cells keratin 19 with or without keratin 14. This suggests that the keratin 14-positive, smooth muscle proteins-negative duct basal cells are luminal cell progenitors. Luminal cells in tubular structures of both tumors were positive for keratin 19 with or without keratin 14. Nonluminal peripheral cells of pleomorphic adenomas were mostly positive for keratin 14, and a small fraction of them expressed smooth muscle proteins. Conversely, peripheral cells of adenoid cystic carcinomas were mostly positive for smooth muscle proteins, and some of them expressed keratin 14. These results strongly suggest (1) that the luminal cell progenitors transform into major constituents of pleomorphic adenoma cells with keratin 14 but not smooth muscle proteins, and (2) that the peripheral cells of adenoid cystic carcinoma are derived from undifferentiated MECs. Solid structures of pleomorphic adenomas were formed by proliferation of the peripheral cells. MECs were observed only occasionally in the periphery. Solid and cribriform structures of adenoid cystic carcinomas were formed by proliferation of the luminal cells. MECs were observed in the periphery and around the pseudocyst. [ABSTRACT FROM AUTHOR]

A very rare case of benign fibrous histiocytoma of the mandible is presented. A 49-year-old woman was admitted because of left buccal swelling and pain. Panoramic radiograph showed well-demarcated soap-bubble appearance without sclerotic rim in the left mandibular bone. A yellowish-white and partly brown solid tumor was noted in the excised mandibular bone specimen. The tumor histologically consisted of spindle cells, in which areas showing a storiform pattern and other areas composed of histiocytic cells with erythrophagocytosis and foam cells were mixed. Immunohistochemically, the tumor cells were positive for vimentin, CD68, alpha-1-antichymotrypsin and alpha-1-antitrypsin. From these findings the tumor was diagnosed as a primary BFH of the mandible. No recurrence has been noted 2 years and 11 months after surgery. [ABSTRACT FROM AUTHOR]

Angiogenesis plays an important role in cancer growth and metastasis, and it is considered a therapeutic target to control tumour growth following anti-angiogenic therapy. However, it is still unclear when tissues initiate angiogenesis during malignant transformation from premalignant condition and whether this premalignant condition could be a therapeutic target of anti-angiogenic therapy. In this study, we aimed to analyse the onset of angiogenesis by evaluating morphological and functional alterations of microvessels during oral multistep carcinogenesis using a 4-nitroquinoline 1-oxide (4NQO)-induced oral carcinogenesis mouse model. In the study, we initially confirmed that with the use of 4NQO, oral lesions develop in a stepwise manner from normal mucosa through oral epithelial dysplasia (OED) to oral squamous cell carcinoma (OSCC). Evaluation of CD31-immunostained specimens revealed that microvessel density (MVD) increases in a stepwise manner from OEDs. Histological and functional analyses revealed the structural abnormalities and leakage of blood vessels had already taken place in OED. Then we evaluated the expression profiles of Hif1a and Vegfa along with hypoxic status and found that OED exhibited increased Vegfa expression under hypoxic conditions. Finally, we tested the possibility of OEDs as a target of anti-angiogenic therapy and found that anti-VEGFR2 neutralising antibody in OED slowed the disease progression from OED to OSCC. These data indicate that an angiogenic switch occurs at the premalignant stage and morphological, and functional alterations of microvessels already exist in OED. These findings also elucidate the tumour microenvironment, which gradually develops along with carcinogenic processes, and highlight usefulness of the 4NQO-induced carcinogenesis model in the study of epithelial and stromal components, which will support epithelial carcinogenesis. © 2024 The Author(s). The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland., (© 2024 The Author(s). The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.)

Background: Squamous cell carcinoma (SCC) of the dorsum of the tongue is extremely rare, and it clinically resembles various benign lesions. Somatic mutations in TP53 and some driver genes were implicated in the development of SCC; however, the somatic genetic characteristics of dorsal tongue SCC remain unknown. With a detailed analysis of gene mutations in dorsal tongue SCC, we aimed to better understand its biology., Methods: Four cases of SCC initially occurring on the tongue dorsum were evaluated for clinical and histological findings and immunohistochemical expression of p53 and p16. Gene mutations were analyzed using next-generation sequencing with a custom panel of driver genes., Results: We retrospectively investigated 557 cases of tongue SCC, and only four cases of SCC initially occurred on the tongue dorsum. The four patients (cases 1-4) were one woman and three men with a mean age of 53.75 years (range: 15-74 years). Histological analysis revealed well-differentiated SCC. Through molecular analysis, we identified pathogenic somatic mutations, namely, TP53 p.C176F (c.527G > T) in case 3 and TP53 p.R282W (c.844 C > T) in case 4. No pathogenic variants were identified in the PI3K/AKT or RAS/RAF pathways. The p53 immunohistochemical examination revealed a wild-type expression pattern in cases 1-3 and strong expression in case 4. The results of p16 immunostaining were negative in all cases., Conclusions: We described four previously unreported genetic characteristics of dorsal tongue SCC. Somatic TP53 mutations may contribute to the development of a subset of dorsal tongue SCC; however, more cases with genetic analysis need to be accumulated., (© 2024. The Author(s).)

Background: Cementoblastoma is a rare odontogenic tumor characterized by the formation of osteocementum-like tissue on a tooth root directly by neoplastic cementoblasts. Although it is categorized as benign, it has a high potential for growth with a certain degree of recurrence risk. However, there are only a few studies describing the features of recurrent cementoblastoma. The diagnosis of recurrent cementoblastoma is challenging not only due to its cytological atypia but also because of its large size and multicentric growth pattern. These characteristics suggest a potential for malignancy., Case Presentation: A 29-year-old woman was transferred to our university dental hospital complaining of swelling of the right mandible. She had a history of enucleation of cementoblastoma associated with the third molar of the right mandible. Five years after the initial treatment, imaging demonstrated well-circumscribed multicentric radiopaque lesions in the same area. Histologically, the lesion consisted of osteocementum-like tissue rimmed with polygonal or plump tumor cells. Several cells were large epithelioid cells with bizarre nucleoli, which may be reminiscent of malignant tumors. Otherwise, there were no apparent malignant findings, including proliferative activity or atypical mitotic figure. Besides, tumor cells were positive for c-FOS, a marker of osteoblastoma and cementoblastoma. Eventually, the patient was diagnosed with recurrent cementoblastoma., Conclusions: Pathological analyses of this case suggested that the recurrent event in the cementoblastoma altered its growth pattern and tumor cell shape. Moreover, in the case of enucleation surgery, long-term follow-up is important because there is some recurrent risk of cementoblastoma, although it is not high., (© 2024. The Author(s).)

Venous malformations (VMs) are the most common vascular malformations. TEK and PIK3CA are the causal genes of VMs, and may be involved in the PI3K/AKT pathway. However, the downstream mechanisms underlying the TEK or PIK3CA mutations in VMs are not completely understood. This study aimed to identify a possible association between genetic mutations and clinicopathological features. A retrospective clinical, pathological, and genetic study of 114 patients with VMs was performed. TEK, PIK3CA, and combined TEK/PIK3CA mutations were identified in 49 (43%), 13 (11.4%), and 2 (1.75%) patients, respectively. TEK-mutant VMs more commonly occurred in younger patients than TEK and PIK3CA mutation-negative VMs (other-mutant VMs), and showed more frequent skin involvement and no lymphocytic aggregates. No significant differences were observed in sex, location of occurrence, malformed vessel size, vessel density, or thickness of the vascular smooth muscle among the VM genotypes. Immunohistochemical analysis revealed that the expression levels of phosphorylated AKT (p-AKT) were higher in the TEK-mutant VMs than those in PIK3CA-mutant and other-mutant VMs. The expression levels of p-mTOR and its downstream effectors were higher in all the VM genotypes than those in normal vessels. Spatial transcriptomics revealed that the genes involved in "blood vessel development", "positive regulation of cell migration", and "extracellular matrix organization" were up-regulated in a TEK-mutant VM. Significant genotype-phenotype correlations in clinical and pathological features were observed among the VM genotypes, indicating gene-specific effects. Detailed analysis of gene-specific effects in VMs may offer insights into the underlying molecular pathways and implications for targeted therapies., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: Squamous cell carcinoma (SCC) is the most common oral malignancy, and somatic mutations in some driver genes have been implicated in SCC development. Clear cell SCC (CCSCC) is a rare histological variant of SCC, and various clear cell neoplasms must be considered in the differential diagnosis of CCSCC in the oral cavity. Based on a limited number of CCSCC cases reported in the oral cavity, CCSCC is considered an aggressive variant of SCC with a poor prognosis; however, its genetic characteristics remain unknown., Methods: A maxillary gingival tumor in an 89-year-old female was described and investigated using immunohistochemical staining, special staining, fluorescence in situ hybridization, and next-generation sequencing (NGS) with a custom panel of driver genes, including those associated with SCC and clear cell neoplasm development., Results: Histopathological examination revealed a proliferation of atypical epithelial cells with abundant clear cytoplasm and enlarged and centrally placed round nuclei. The tumor was exophytic with deep, penetrating proliferation. The atypical clear cells were continuous with the conventional SCC cells. Immunohistochemical analysis showed that the clear cells were positive for CK AE1/AE3 and CK5/6 and nuclear-positive for p63. In contrast, the clear cells were negative for αSMA, S100, HMB45, Melan-A, CD10, and p16. p53 immunoreactivity exhibited a wild-type expression pattern. Additionally, the clear cells were positive for periodic acid-Schiff (PAS) and negative for diastase-PAS, mucicarmine, and Alcian blue. Based on these results, the diagnosis of CCSCC was confirmed. Molecular analysis of the clear cells identified PIK3CA p.E542K (c.1624G>A) and HRAS p.G12A (c.35 G>C) somatic mutations classified as oncogenic. No pathogenic variants were identified in TP53, EWSR1, AKT1, PTEN, BRAF, KRAS, NRAS, RASA1, or MAML2., Conclusions: We report a case of CCSCC of the oral cavity with PIK3CA and HRAS mutations. The identification of PIK3CA and/or HRAS mutations is rare in SCC; however, both mutations are important potential targets for antitumor therapy. A detailed analysis of gene mutations in CCSCC may lead to a better understanding of its biological behavior and an improved prognosis, as well as a differential diagnosis from other clear cell neoplasms., (© 2023. The Author(s).)

The main purpose of cytological examination in the oral region is to screen for squamous cell carcinoma or intraepithelial neoplasms; thus, the background tends to be considered a deterrent for microscopy. From this perspective, liquid-based cytology (LBC) is favorable for preparing clear samples with few backgrounds. However, background hemocytes are sometimes of critical importance in the diagnosis. We report two cases of oral malignant lymphoma, plasmablastic lymphoma, and anaplastic large cell lymphoma in which careful observation of the background in scraping LBC sample contributed to the early diagnosis. Atypical lymphoid cells were observed only in a very small part of the LBC samples from the presented patients; however, cytological findings, such as large lymphoid cells with outstanding nucleoli, large mitotic cells, or intermediate-to-large lymphoid cells with pleomorphic nuclei were sufficient for obtaining a cytological diagnosis of malignant lymphoma. Although the number and cell size of leukocytes in LBC with Papanicolaou staining were significantly different from those in air-dried conventional smears with Romanovsky staining, which are commonly preferred for the discrimination of hemocytes, the corresponding cytological features could be observed. Therefore, attention should be paid to the background as well as squamous epithelium to prepare for such unexpected cases. The LBC examination with Papanicolaou staining alone can suggest the possibility of malignant lymphoma., Competing Interests: Declaration of competing interest The authors have no conflicts of interest relevant to this article., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

Osteoclasts play a crucial role in bone homeostasis by forming resorption pits on bone surfaces, resulting in bone resorption. The osteoclast expression of Rab38 protein is highly induced during differentiation from macrophages. Here we generated mice with double knockout (DKO) of Rab38 and its paralogue, Rab32, to investigate the roles of these proteins in osteoclasts. Bone marrow-derived macrophages from Rab32/38 DKO mice differentiated normally into osteoclasts in vitro. However, DKO osteoclasts showed reduced bone resorption activity. These osteoclasts also demonstrated defective secretion of tartrate-resistant acid phosphatase and cathepsin K into culture medium. Furthermore, the plasma membrane localization of a3, an osteoclast-specific a subunit of V-ATPase, was abrogated in DKO mice, substantiating the reduced resorption activity. In vivo, Rab32- and Rab38-positive cells were attached to the bone surface. Eight-week-old DKO mice showed significantly thickened trabecular bones in micro-CT and histomorphometry analysis, as well as reduced serum levels of cross-linked C-telopeptide of type I collagen, indicating diminished bone resorption in vivo. In DKO male mice over 10 weeks of age, hyperostosis appeared at the talofibular syndesmosis, the distal junction of the tibia and fibula. Furthermore, middle-aged mice (10 to 12 months of age) exhibited kyphosis, which is not usually observed in wild-type male mice until around 24 months of age. These results indicate that Rab32 and Rab38 contribute to osteoclast function by supporting intracellular traffic, thereby maintaining normal bone homeostasis.Key words: Rab32, Rab38, osteoclast, lysosome-related organelle, secretory lysosome.

FAM20C phosphorylates secretory proteins at S-x-E/pS motifs, and previous studies of Fam20C-dificient mice revealed that FAM20C played essential roles in bone and tooth formation. Inactivation of FAM20C in mice led to hypophosphatemia that masks direct effect of FAM20C in these tissues, and consequently the direct role of FAM20C remains unknown. Our previous study reported that osteoblast/odontoblast-specific Fam20C transgenic (Fam20C-Tg) mice had normal serum phosphate levels and that osteoblastic FAM20C-mediated phosphorylation regulated bone formation and resorption. Here, we investigated the direct role of FAM20C in dentin using Fam20C-Tg mice. The tooth of Fam20C-Tg mice contained numerous highly phosphorylated proteins, including SIBLINGs, compared to that of wild-type mice. In Fam20C-Tg mice, coronal dentin volume decreased and mineral density unchanged at early age, while the volume unchanged and the mineral density elevated at maturity. In these mice, radicular dentin volume and mineral density decreased at all ages, and histologically, the radicular dentin had wider predentin and abnormal apical-side dentin with embedded cells and argyrophilic canaliculi. Immunohistochemical analyses revealed that abnormal apical-side dentin had bone and dentin matrix properties accompanied with osteoblast-lineage cells. Further, in Fam20C-Tg mice, DSPP content which is important for dentin formation, was reduced in dentin, especially radicular dentin, which might lead to defects mainly in radicular dentin. Renal subcapsular transplantations of tooth germ revealed that newly formed radicular dentin replicated apical abnormal dentin of Fam20C-Tg mice, corroborating that FAM20C overexpression indeed caused the abnormal dentin. Our findings indicate that odontoblastic FAM20C-mediated phosphorylation in the tooth regulates dentin formation and odontoblast differentiation., (© 2023. The Author(s), under exclusive licence to Springer Nature B.V.)

Background: Dentinogenic ghost cell tumor is a rare benign tumor that accounts for less than 3% of all cases and consists of the stellate reticulum, which is made up of enamel epithelioid and basaloid cells. Although DGCT is a benign tumor, the local infiltration of the odontogenic epithelium or recurrences have been reported, and its detailed pathology and treatments remain unclear., Case Presentation: This report describes the case of a 60-year-old Japanese male diagnosed with a maxillary dentinogenic ghost cell tumor. Images showed well-circumscribed, multilocular cystic lesions with a calcified substance in the interior. Marsupialization was performed along with biopsy to prevent the expansion of the lesion, and a partial maxillectomy was performed 2 years after the initial examination. Histopathological findings showed ameloblastomatous proliferation containing clusters of ghost cells and dentinoid materials, resulting in the diagnosis of dentinogenic ghost cell tumor. This article also reviews recently reported cases of dentinogenic ghost cell tumor., Conclusion: It is important to perform marsupialization, proper resection, and postoperative follow-up because of possible recurrence., (© 2023. The Author(s).)

Background: Although cervical lymph node metastasis is an important prognostic factor for oral cancer, occult metastases remain undetected even by diagnostic imaging. We developed a learning model to predict lymph node metastasis in resected specimens of tongue cancer by classifying the level of immunohistochemical (IHC) staining for angiogenesis- and lymphangiogenesis-related proteins using a multilayer perceptron neural network (MNN)., Methods: We obtained a dataset of 76 patients with squamous cell carcinoma of the tongue who had undergone primary tumor resection. All 76 specimens were IHC stained for the six types shown above (VEGF-C, VEGF-D, NRP1, NRP2, CCR7, and SEMA3E) and 456 slides were prepared. We scored the staining levels visually on all slides. We created virtual slides (4560 images) and the accuracy of the MNN model was verified by comparing it with a hue-saturation (HS) histogram, which quantifies the manually determined visual information., Results: The accuracy of the training model with the MNN was 98.6%, and when the training image was converted to grayscale, the accuracy decreased to 52.9%. This indicates that our MNN adequately evaluates the level of staining rather than the morphological features of the IHC images. Multivariate analysis revealed that CCR7 staining level and T classification were independent factors associated with the presence of cervical lymph node metastasis in both HS histograms and MNN., Conclusion: These results suggest that IHC assessment using MNN may be useful for identifying lymph node metastasis in patients with tongue cancer., (© 2022 The Authors. Cancer Medicine published by John Wiley & Sons Ltd.)

Background/purpose: Diagnostic methods of oral squamous cell carcinoma (SCC) using artificial intelligence (AI) and digital-histopathologic images have been developed. However, previous AI training methods have focused on the cellular atypia given by the training of high-magnification images, and little attention has been paid to structural atypia provided by low-power wide fields. Since oral SCC has histopathologic types with bland cytology, both cellular atypia and structural atypia must be considered as histopathologic features. This study aimed to investigate AI ability to judge oral SCC in a novel training method considering cellular and structural atypia and their suitability., Materials and Methods: We examined digitized histological whole-slide images from 90 randomly selected patients with tongue SCC who attended a dental hospital. Image patches of 1000 × 1000 pixels were cut from whole-slide images at 0.3125-, 1.25-, 5-, and 20-fold magnification, and 90,059 image patches were used for training and evaluation. These image patches were resized into 224 × 224, 384 × 384, 512 × 512, and 768 × 768 pixels, and the differences in input size were analyzed. EfficientNet B0 was utilized as the convolutional neural network model. Gradient-weighted class activation mapping (Grad-CAM) was used to elucidate its validity., Results: The proposed method achieved a peak accuracy of 99.65% with an input size of 512 × 512 pixels. Grad-CAM suggested that AI focused on both cellular and structural atypia of SCC, and tended to focus on the region surrounding the basal layer., Conclusion: Training AI regarding both cellular and structural atypia using various magnification images simultaneously may be suitable for the diagnosis of oral SCC., Competing Interests: The authors have no conflicts of interest relevant to this article., (© 2022 Association for Dental Sciences of the Republic of China. Publishing services by Elsevier B.V.)

Proinflammatory cytokines play critical roles in the pathogenesis of joint diseases. Using a mass spectrometry-based cloning approach, we identified Semaphorin 4D (Sema4D) as an inflammatory cytokine that directly promoted cartilage destruction. Sema4d -deficient mice showed less cartilage destruction than wild-type mice in a model of rheumatoid arthritis. Sema4D induced a proinflammatory response in mouse articular chondrocytes characterized by the induction of proteolytic enzymes that degrade cartilage, such as matrix metalloproteinases (MMPs) and aggrecanases. The activation of Mmp13 and Mmp3 expression in articular chondrocytes by Sema4D did not depend on RhoA, a GTPase that mediates Sema4D-induced cytoskeletal rearrangements. Instead, it required NF-κB signaling and Ras-MEK-Erk1/2 signaling downstream of the receptors Plexin-B2 and c-Met and depended on the transcription factors IκBζ and C/EBPδ. Genetic and pharmacological blockade of these Sema4D signaling pathways inhibited MMP induction in chondrocytes and cartilage destruction in femoral head organ culture. Our results reveal a mechanism by which Sema4D signaling promotes cartilage destruction.

Background: Orthokeratinized odontogenic cyst (OOC) is a rare developmental odontogenic cyst of the jaw. It was originally believed to be a variant of odontogenic keratocyst (OKC) but is now considered to be a distinct entity. OOC usually presents as a single lesion and recurs infrequently. On the other hand, OKC often presents with multiple lesions and displays locally aggressive behavior and a high recurrence rate associated with the protein patched homolog 1 (PTCH1) gene mutation. Multiple OOC cases are extremely rare and seem to be aggressive, but their pathogenesis is not fully understood. This study aimed to determine the clinical, pathological, and genetic characteristics of multiple OCC., Methods: Three cases of multiple OOC were evaluated for clinical and histological findings, and immunohistochemical expression of Ki-67 and Bcl-2. Furthermore, PTCH1 mutations were analyzed by next-generation sequencing using a custom panel to cover the entire exon of PTCH1., Results: The three cases of multiple OOC included two men and one woman with a mean age of 25.3 years old (range, 18-38 years old). Each case had two or three OOCs (total of seven OOCs), all of which were simultaneously detected. Of the seven OOCs that manifested as multiple jaw cysts, seven (100%) occurred in the posterior regions, four (57.1%) occurred in the mandible, and four (57.1%) were associated with an impacted tooth. Histological examination revealed cysts lined by orthokeratinized stratified squamous epithelium. Immunohistochemistry showed a low Ki-67 labeling index and no Bcl-2 expression in the seven OOCs. No pathogenic PTCH1 mutations were detected in any of the seven OOCs. None of the patients had any other symptoms or signs of recurrence at the last follow-up (6-60 months)., Conclusion: Multiple OOCs appeared to occur more often in younger patients than solitary OOC. Both multiple and solitary OOCs may be related diseases within the entity of odontogenic cysts. Multiple OOCs are clinicopathologically and genetically distinct from OKC., (© 2022. The Author(s).)

Objectives: This study sought to identify tumor characteristics that associate with regional lymph node metastases in squamous cell carcinomas originating in the upper gingiva., Materials and Methods: Data from 113 patients from Osaka University Dental Hospital were included. We measured each primary tumor's width, length, depth, and the extent of bone invasion. Additionally, tumor signal intensity for T1 and T2-weighted images as well as the center of the tumor's location and T classification was assessed, and a histopathological analysis was performed., Results: Tumor signal intensity was not found to be a significant prognostic factor. However, bucco-lingual width, histopathological classification as well as the tumor's location were significantly different between metastatic and non-metastatic groups in both univariate and multivariate analysis. Superior-inferior depth and T classification were significant only in the univariate (and not the multivariate) analysis., Conclusions: Bucco-lingual width, histopathological grading as well as the tumor's location are likely to be important predictors for the occurrence of LN metastasis in upper gingival carcinoma patients and should be considered when managing care for these patients., (© 2021. The Author(s).)

High-dose-rate interstitial brachytherapy (HDR-ISBT) has recently come to be considered one of the most effective treatments for oral cancer. On the other hand, it is important to note that radiation therapy has some side effects. Especially, radiation-induced malignancy is probably the most serious complication affecting long-term survivors. We report a case of a radiation-induced undifferentiated spindle cell sarcoma that developed following HDR-ISBT for tongue squamous cell carcinoma (SCC). A 39-year-old woman with right tongue SCC underwent HDR-ISBT (60 Gy, 10 fractions, 8 days) treatment. Five years and one month later, a tumor had developed at the primary site. Surgery was performed for the tumor, which was histopathologically diagnosed as an undifferentiated spindle cell sarcoma. That was distinct from the squamous cell origin of the primary cancer. According to recently established criteria for radiation-induced malignancy, this case was classified as a radiation-induced sarcoma. A search of the literature revealed no previous report of radiation-induced malignancy following HDR-ISBT for tongue cancer., Competing Interests: The authors report no conflict of interest., (Copyright © 2022 Termedia.)

Clear cell carcinoma (CCC) is a rare epithelial malignant tumor of the salivary glands. It is characterized by tumor cells with clear cytoplasm, hyalinized stroma, and most importantly the fusion genes EWSR1-ATF1, EWSR1-CREM, and EWSR1-PLAG1. Break-apart FISH has been performed for multiple CCC cases, but direct sequencing analysis has been performed in relatively few. Herein, we report an interesting case of CCC harboring three EWSR1-ATF1 translocations: EWSR1 exon 8-ATF1 exon 4, EWSR1 exon 7-ATF1 exon 4, and EWSR1 exon 7-ATF1 exon 5. This case indicates the possibility of independent EWSR1-ATF1 gene translocations, and could provide insight into CCC tumorgenesis., (© 2021. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Background: Tumor immunity in the tumor microenvironment is activated in patients with feasible clinical responses to immune checkpoint inhibitors. The immunological profile of tumor-infiltrating lymphocytes (TILs) obtained from patients with oral squamous cell carcinoma (OSCC) was examined in relation to their prognosis., Materials and Methods: Surface antigens, including immune checkpoint molecules, on TILs from 31 patients with primary OSCC were analyzed by flow cytometry. The activation status of TILs was examined through a heatmap analysis and unsupervised clustering classified patients into groups with activated or inactivated TILs. A supervised machine-learning algorithm for single-cell analyses in relation to prognosis was run using the Cluster Identification, Characterization, and Regression (CITRUS) program., Results: None of surface antigens were related to prognosis. The CITRUS program revealed a relationship between CD45RA - CD4 + CD25 high inducible T-cell co-stimulator (ICOS) + TILs and recurrence, and also identified a similar fraction significantly specific to the group with activated TILs. The disease-free survival rate for patients with ≥95% ICOS + TILs was significantly lower than that for those with <95% ICOS + TILs. Furthermore, a review of clinicopathological factors related to prognosis identified the percentage of ICOS + TILs to be an independent prognostic factor for patients with OSCC., Conclusion: CD25 high ICOS + regulatory T-cells in TILs have potential as a biomarker for predicting recurrence after surgical treatment and clinical responses to immune checkpoint inhibitors in patients with OSCC., (Copyright © 2022 International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.)