Intramuscular Myxoma of the Intrinsic Muscles of the Tongue: A Case Report with Literature Review.

Myxoma is a benign tumor of mesenchymal origin. It frequently occurs in the muscles of the hip and extremities; however, it rarely occurs in the head and neck region. This report describes the second case of an intramuscular myxoma of the tongue. A 23-year-old woman was referred to our institution for the diagnosis and treatment of a left tongue lesion. T2-weighted magnetic resonance imaging revealed an 8 × 6-mm mass in the tongue. Based on a clinical diagnosis of a tongue tumor, excisional biopsy was performed under general anesthesia. The histopathological diagnosis was an intramuscular myxoma. The postoperative course was uneventful, and there was no evidence of tumor recurrence 3 years after surgery.

Hypoproteinemia Associated with a Gigantic Odontogenic Tumor: A Report of 2 Cases.

BACKGROUND Hypoproteinemia is caused by a decrease in protein level in the blood. This report describes 2 cases of hypoproteinemia associated with a gigantic odontogenic tumor. CASE REPORT Case 1, a 65-year-old man, visited our hospital with the chief concern of swelling in the right mandible, approximately 100 mm in diameter, and ameloblastoma was diagnosed. Abscess drainage was observed in the fistula of the tumors. Total protein and albumin levels were low before surgery. Hemimandibulectomy was performed under general anesthesia. The final pathological diagnosis based on the specimen was ameloblastic carcinoma. After surgery, the total protein and albumin levels improved and remained stable 6 months after the operation. At 21 months after surgery, there were no signs of recurrence. Case 2, a 60-year-old woman, visited our hospital with a chief concern of swelling in the left mandible, approximately 100 mm in diameter, and ameloblastoma was diagnosed. Abscess drainage was observed in the fistula of the tumors. The patient had a history of hypoproteinemia; preoperative levels of total protein and albumin were low, and edema of the body was observed before surgery. Hemimandibulectomy was performed under general anesthesia. The final pathological diagnosis based on the specimen was ameloblastoma. After surgery, the total protein and albumin levels improved, and remained stable 6 weeks after surgery. There were no signs of recurrence 9 months after surgery. CONCLUSIONS These 2 cases indicate the possibility that hypoproteinemia can be caused by plasma leakage from fistulas associated with gigantic odontogenic tumors.

A case of solitary neurofibroma in the maxillary gingiva.

Neurofibromas are benign tumors. They are known to be a manifestation of von Recklinghausen's disease (neurofibromatosis type 1) and tend to be generalized and rarely solitary. In this report, we present a case of solitary neurofibroma in the maxillary gingiva. A 39-year-old woman presented with a chief complaint of swollen gingiva. There were no special findings in her medical or family history. After a biopsy was performed under local anesthesia and a diagnosis of neurofibroma was made, tumor resection was performed under general anesthesia. The patient's progress was good, with no recurrence.

Rare papular presentation of an elastofibromatous lesion of the alveolar mucosa.

A 72-year-old Japanese female patient presented with an asymptomatic, white-colored, smooth-surfaced, firm papule 3 mm in diameter involving the mucosa on the posterior part of the right maxilla. An excisional biopsy specimen was diagnosed as an oral focal submucous elastofibromatous lesion. A review of the literature revealed very few documented cases of oral mucosal lesions characterized by accumulation of degenerated elastic fibers. Various oral lesions have histopathological features similar to those observed in cutaneous diseases, and the present case was a focal submucous elastofibromatous lesion in the alveolar mucosa.

Diagnostic Accuracy of High-Grade Intraepithelial Papillary Capillary Loops by Narrow Band Imaging for Early Detection of Oral Malignancy: A Cross-Sectional Clinicopathological Imaging Study.

This study aimed to clarify the advantages and disadvantages of conventional visual inspection (CVI), endoscopic white light imaging (WLI), and narrow-band imaging (NBI) and to examine the diagnostic accuracy of intraepithelial papillary capillary loops (IPCL) for the detection of oral squamous cell carcinoma (OSCC). This cross-sectional study included 60 participants with oral mucosal diseases suspected of having oral potentially malignant disorders (OPMDs) or OSCC. The patients underwent CVI, WLI, NBI, and incisional biopsy. Images were evaluated to assess the lesion size, color, texture, and IPCL. Oral lichen planus (OLP) and oral leukoplakia lesions were observed in larger areas with NBI than with WLI; 75.0% were associated with low-grade (Type 0-II) IPCL. Various types of oral leukoplakia were seen; however, all OSCC cases showed high-grade (Type III-IV) IPCL. The diagnostic accuracy of high-grade IPCL for OSCC showed a sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of 100%, 80.9%, 59.1%, 100%, and 85.0%, respectively. A non-homogeneous lesion with high-grade IPCL strongly suggested malignancy. Overall, our results indicate that WLI and NBI are powerful tools for detecting precancerous and cancerous lesions using IPCL. However, NBI is influenced by mucosal thickness; therefore, image interpretation is important for accurate diagnosis.

Osteosarcoma of the Mandible in an Elderly Patient.

Osteosarcoma is a malignant tumor in which the cancerous cells produce an osteoid matrix or mineralized bone. Jaw bones are affected in 6% of all osteosarcomas and are the fourth most common site of origin. Surgical treatment of osteosarcoma in elderly patients is rarely reported. Here, we report successful treatment of osteosarcoma arising in the mandible of a 90-year-old man. The patient was referred to our institution for diagnosis and treatment of an oral lesion. Intraoral examination revealed that a hard mass measuring 35 × 27 mm was located on the floor of the oral cavity, attached to the bone, and its growth displaced the tongue posteriorly. Therefore, he experienced difficulty in speech and swallowing. Biopsy of the mandibular mass was suspicious for chondrosarcoma. Preoperative examination did not detect critical risks for general anesthesia or surgery. Based on a clinical diagnosis of a malignant bone tumor of the mandible, segmental mandibular resection with reconstruction using a titanium plate was performed. Surgical site infection occurred on postoperative day 12, which was resolved by drainage, local irrigation, and administration of antibiotics. There was no delirium or cardiovascular or pulmonary complications. Surgery resolved the patient's difficulties in speech and swallowing. There was no evidence of tumor recurrence or metastasis 4 years after surgery. This case showed that it was not necessary to exclude surgical treatment merely because the patient was 90 years old. Indications for surgery should be determined individually to improve the patient's quality of life.

A case of canalicular adenoma with anemia.

An 81-year-old woman presented with bleeding from a soft elastic bulge on the right buccal mucosa. Her medical history included hypertension, chronic renal failure, hysterectomy and a goiter operation. Certain investigations, such as blood tests, which confirmed the minimum hemoglobin level of 5.3 g/dl, computed tomography and magnetic resonance imaging (MRI), were conducted. MRI revealed features confirming the presence of a tumor involving the right buccal mucosa with high signal in T2-enhanced image. Considering the provisional diagnosis and image findings, the tumor mass was excised and histopathological examination of the biopsy specimen confirmed the diagnosis of a canalicular adenoma. Under the diagnosis of various clinical departments, the anemic state of the patient might be chiefly attributed to the bleeding from the tumor. Herein, we report a rare case of a canalicular adenoma in the right buccal mucosa with anemia due to bleeding from the tumor.

Rhabdomyosarcoma in the maxillary gingiva of a child patient.

Rhabdomyosarcoma (RMS) is a rare, rapidly growing and aggressive malignant neoplasm mainly affecting children. However, mean age at the diagnosis of patients with gingival RMS is 26.9 years. A 12-year-old girl presented to our clinic with a chief complaint of trismus. The examination findings indicated a malignant tumor in the left maxillary gingiva. We performed a biopsy of the tumor, and the histopathological diagnosis was RMS. We report a rare case of primary RMS of the maxillary gingiva in a child patient.

Primary epithelioid angiosarcoma originating from the mandibular gingiva: a case report of an extremely rare oral lesion.

BACKGROUND: Angiosarcoma occurs very rarely in the oral cavity, and the epithelioid type is even rarer. Here, we report a rare case involving an elderly man with a primary epithelioid angiosarcoma that originated from the mandibular gingiva and resembled a dentigerous cyst on radiographs. CASE PRESENTATION: A 66-year-old Japanese man visited our hospital with a chief complaint of gingival swelling in right mandibular third molar region. A panoramic radiograph showed bone resorption around the crown of right mandibular third molar, which was impacted. Incisional biopsy confirmed a diagnosis of epithelioid angiosarcoma. The lesion exhibited aggressive proliferation after biopsy resulting in uncontrolled bleeding and difficulty in closing the mouth. Mandibular segmental resection including the tumor was performed without reconstruction. Because of the aggressive preoperative course of the tumor, the patient received adjuvant chemotherapy. There were no signs of recurrence during a 2-year follow-up period. CONCLUSIONS: A review of the literature yielded only four reported cases of epithelioid angiosarcoma in the jaw region, with the lesions occurring in the maxilla in three cases. To our knowledge, this is the second case of primary epithelioid angiosarcoma in the mandible.

Cystadenoma of the tongue: report of a case with long-term follow-up.

Cystadenoma is a rare benign salivary gland neoplasm characterized by a predominantly multicystic growth pattern. The parotid gland is involved in about 45-50% of cystadenoma cases, with the minor glands of the lip and buccal mucosa being the next most common sites. The tongue is rarely involved; only one congenital case is reported in the literature. Here, we report a 63-year-old man who was referred to our hospital for a nodule on the right edge of his tongue that developed into an elastic soft mass, 4 mm in diameter. It was clinically diagnosed as a benign tumour and removed under local anaesthesia. Microscopically, the lesion was composed of multiple cysts of various sizes and shapes, with or without papillary intraluminal short projections. It was diagnosed as cystadenoma. The postoperative course was uneventful, and we found no evidence of recurrence at the postoperative 14-year follow-up.

Effects of butyric acid, a bacterial metabolite, on the migration of ameloblastoma mediated by laminin 332.

Ameloblastoma is a benign tumor that develops in the jawbone. Occasionally, however, it may become malignant and metastasize to other tissues. Although it has been suggested that various cytokines and several adhesion factors may play a role in its malignant transformation, the details have not been elucidated. In this context, it has been reported that butyric acid produced by periodontopathic bacteria causes progression of malignant tumors occurring in the mouth via podoplanin. However, the influence of butyric acid on ameloblastoma has not been clarified. In the present study, therefore, the expression of various cytokines and adhesion factors in ameloblastoma upon stimulation with butyric acid or cytokines was investigated using real-time reverse-transcription polymerase chain reaction. Three cell lines (HAM1, HAM2 and HAM3) established from the same ameloblastoma were used in the experiments. It was found that the expression of mRNAs for epidermal growth factor (EGF) and transforming growth factor beta 1 (TGFß1) was increased in HAM2 and HAM3, respectively, upon stimulation with butyric acid. In addition, stimulation with EGF and TGFß1 led to an increase in the expression of laminin ß-3 mRNA in the respective cell lines. These results suggest that butyric acid may be involved in ameloblastoma exacerbation through the expression of laminin 332 (LM332) via EGF and TGFß1 produced by ameloblastoma itself.

Detection of MAPK/ERK pathway proteins and KRAS mutations in adenomatoid odontogenic tumors.

OBJECTIVE: This study aimed to assess the frequency of KRAS mutation and its association with the presence of the MAPK/ERK signaling pathway proteins in adenomatoid odontogenic tumors. STUDY DESIGN: Paraffin-embedded tissue samples from nine cases of adenomatoid odontogenic tumor were used. Genomic DNA was extracted from each sample; in one case, genetic mutations in 50 cancer-associated genes were examined by next-generation sequencing. Hotspot mutations in the RAS family were analyzed by Luminex assay using the remaining eight cases. Subsequently, immunohistochemistry for KRAS, CRAF, BRAF, EGFR, ERK, MEK, and BRAFV600E was performed. RESULTS: A KRAS G12D missense mutation was detected in the DNA sequence of the tumor cells, but it was not detected in the stromal tissue. KRAS G12V and KRAS G12R mutations were detected in two and four cases, respectively. For immunohistochemistry, all the cases were EGFR, KRAS, BRAF, CRAF positive, one case was ERK negative,and one case was MEK and ERK negative, all the other remaining cases were MEK and ERK positive. CONCLUSION: KRAS mutation at codon 12 and the presence of MAPK/ERK pathway proteins were detected suggesting their association with tumorigenesis of adenomatoid odontogenic tumors.

Pathogenesis of primordial odontogenic tumour based on tumourigenesis and odontogenesis.

OBJECTIVE: Primordial odontogenic tumour (POT) is a rare benign mixed epithelial and mesenchymal odontogenic tumour. POT is composed of dental papilla-like tissue covered with cuboidal to columnar epithelium that resembles to inner and outer enamel epithelium of the enamel organ without dental hard tissue formation. The aim of this study was to examine pathogenesis of POT based on tumourigenesis and odontogenesis. SUBJECTS AND METHODS: Six cases of POT were submitted for study. DNA analysis and transcriptome analysis were performed by next-generation sequencing. Expression of amelogenin, ameloblastin and dentin sialophosphoprotein (DSPP) was examined by immunohistochemistry. RESULTS: There were no gene mutations detected in any of analysed 151 cancer- and 42 odontogenesis-associated genes. Enamel protein-coding genes of Amelx, Ambn and Enam, and dentin protein-coding genes of Col1a1, Dspp, Nes and Dmp1 were expressed, whereas expression of dentinogenesis-associated genes of Bglap, Ibsp and Nfic was negative or very weak suggesting inhibition of dentin formation in POT after odontoblast differentiation. Immunoreactivity of amelogenin, ameloblastin and DSPP was detected in POT. CONCLUSIONS: Pathogenesis of POT is considered to be genetically different from other odontogenic tumours. It is suggested that inhibition of enamel and dentin formation in POT is due to defects in dentin formation process.

Preventive effect of Dioscorea japonica on squamous cell carcinoma of mouse skin involving down-regulation of prostaglandin E2 synthetic pathway.

Hyperproduced prostaglandin E2 by cyclooxygenase-2 and microsomal prostaglandin E synthase-1 evokes several pathophysiological responses such as inflammation and carcinogenesis. Our recent study demonstrated that Dioscorea japonica extract suppressed the expression of cyclooxygenase-2 and microsomal prostaglandin E synthase-1 and induced apoptosis in lung carcinoma A549 cells. In the present study, we investigated the effects of Dioscorea japonica on squamous cell carcinoma of mouse skin. Dioscorea japonica feeding and Dioscorea japonica extract topical application suppressed the expression of cyclooxygenase-2, microsomal prostaglandin E synthase-1, interleukin-1ß and interleukin-6 and inhibited tumor formation, hyperplasia and inflammatory cell infiltration. Immunohistochemical analyses showed the immunoreactivities of cyclooxygenase-2 and microsomal prostaglandin E synthase-1 in tumor keratinocytes and stronger immunoreactivities of cyclooxygenase-2 and hematopoietic prostaglandin D synthase in epidermal dendritic cells (Langerhans cells). Treatment with Dioscorea japonica decreased the immunoreactivity of cyclooxygenase-2 and microsomal prostaglandin E synthase-1. These results indicate that Dioscorea japonica may have inhibitory effects on inflammation and carcinogenesis via suppression of the prostaglandin E2 synthetic pathway.

Primordial Odontogenic Tumor: A case report with histopathological analyses.

Primordial odontogenic tumor (POT) is a benign mixed epithelial and mesenchymal odontogenic tumor included into the current World Health Organization (WHO) classification of Head and Neck tumours in 2017. As far as the authors have confirmed, only eight cases of this tumor have been reported so far. This paper reports a case of POT that occurred in the right mandible of a 5-year-old patient. Panoramic radiograph showed a well-defined homogeneous radiolucency displacing the unerupted second deciduous molar to the deep part of the mandible. Histopathologically, the tumor was composed of cell-rich mesenchymal tissue with myxoid areas, surrounded by columnar epithelium and non-keratinized cuboidal epithelium in the outer layers. The histopathological diagnosis was POT. The expression patterns of cytokeratins (CK) 14, 18, 19, vimentin and CD34 suggested that the grade of differentiation of the POT was approximately equivalent to that of normal primary tooth germ tissues in cap stage to late bell stage.

Expression of Wilms' tumor 1 (WT1) in ameloblastomas.

The Wilms' tumor 1 gene (WT1) was originally isolated and described as the gene responsible for Wilms' tumor. Although there is growing evidence linking the overexpression of WT1 to tumorigenesis, no reports on ameloblastoma are available at present. The aim of this study was to examine the expression of WT1 in various histological subtypes of ameloblastoma tissue specimens and in human ameloblastoma cell lines. Immunohistochemical analyses were performed on a total of 168 cases of ameloblastoma, one case of ameloblastic carcinoma, and five cases of tooth germs (control). Three immortalized human dental epithelial cell lines (HAM1, HAM2, and HAM3) derived from the same ameloblastoma patient were used for reverse transcription-polymerase chain reaction (RT-PCR) and western blot assays. The tooth germs did not express WT1 (0%), and more than half of the ameloblastoma cases showed WT1 overexpression (54.7%). Immunoreactivity of solid-type ameloblastoma (76.1%) was more evident than that of unicystic-type ameloblastoma (40.9%). The expression level of WT1 mRNA in HAM2 was higher than that in HAM1 (moderate) and HAM3 (weak), showing the heterogeneity of tumor cells. The WT1 protein was strongly detected in HAM2 and minimally detected in HAM1 and HAM3. Our results suggest that WT1 expression influences the pathogenesis of ameloblastoma by varying its expression level in different histological types. (J Oral Sci 58, 407-413, 2016).

FAM83H and casein kinase I regulate the organization of the keratin cytoskeleton and formation of desmosomes.

FAM83H is essential for the formation of dental enamel because a mutation in the FAM83H gene causes amelogenesis imperfecta (AI). We previously reported that the overexpression of FAM83H often occurs and disorganizes the keratin cytoskeleton in colorectal cancer cells. We herein show that FAM83H regulates the organization of the keratin cytoskeleton and maintains the formation of desmosomes in ameloblastoma cells. FAM83H is expressed and localized on keratin filaments in human ameloblastoma cell lines and in mouse ameloblasts and epidermal germinative cells in vivo. FAM83H shows preferential localization to keratin filaments around the nucleus that often extend to cell-cell junctions. Alterations in the function of FAM83H by its overexpression, knockdown, or an AI-causing truncated mutant prevent the proper organization of the keratin cytoskeleton in ameloblastoma cells. Furthermore, the AI-causing mutant prevents desmosomal proteins from being localized to cell-cell junctions. The effects of the AI-causing mutant depend on its binding to and possible inhibition of casein kinase I (CK-1). The suppression of CK-1 by its inhibitor, D4476, disorganizes the keratin cytoskeleton. Our results suggest that AI caused by the FAM83H mutation is mediated by the disorganization of the keratin cytoskeleton and subsequent disruption of desmosomes in ameloblasts.

Ultrastructural Analyses of Alveolar Bone in a Patient With Osteomyelitis Secondary to Osteopetrosis: A Review of the Literature.

Osteopetrosis is a generic term for generalized sclerotic conditions caused by rare genetic disorders. Decreased osteoclastic activities disturb bone remodeling, resulting in greater mineral density and greater compressive strength; therefore, bone fracture is a major physical symptom of osteopetrosis. Osteomyelitis of the maxilla or mandible is a common and well-documented complication of osteopetrosis. Local infection, such as odontogenic infection, is more likely to lead to osteomyelitis, and treatment strategies can be challenging. However, detailed ultrastructural analyses of bone from patients with osteopetrosis and odontogenic infection are limited. This report describes a case of osteomyelitis of the maxilla and mandible secondary to osteopetrosis in an adult patient and presents ultrastructural data of alveolar bone tissue analyzed by contact microradiography, electron probe microanalysis, and x-ray diffraction. Cases of osteomyelitis of the jaw secondary to osteopetrosis also are reviewed.

Detection of Rare Variant of SS18-SSX1 Fusion Gene and Mutations of Important Cancer-Related Genes in Synovial Sarcoma of the Lip: Gene Analyses of a Case and Literature Review.

Synovial sarcoma (SS) accounts for 5 to 10% of soft tissue sarcomas; however, intraoral SS is rare. Histopathologically, SS shows a biphasic pattern with epithelial and spindle cell components or a monophasic pattern with only spindle cells. The precise diagnosis of SS, especially at an unusual site, is often a challenge to pathologists and clinical oncologists, because the differential diagnosis of SS includes a broad range of tumors, such as soft tissue sarcomas and carcinomas. In the present case, the patient was a 50-year-old woman who presented with the chief complaint of swelling and a slowly enlarging mass of the lower lip in the mucolabial fold region. The mass was covered with intact mucosa and intraoral examination showed no malignant findings. The clinical diagnosis was a benign tumor and a probable salivary gland tumor. Macroscopically, the excised mass also indicated a benign tumor; however, histopathologic findings suggested the diagnosis of SS. For definitive diagnosis, genetic analyses were performed with conventional polymerase chain reaction and next-generation sequencing. As a result, a rare variant of the SS18-SSX1 fusion transcript, which could not be identified by routine procedures for genetic diagnosis, was detected. In addition, 8 missense mutations of cancer-related genes were confirmed. Detection of the fusion transcript is widely used in the diagnosis of SS; however, reported cases of transcript variants of each fusion gene type are limited. Reports of mutational analysis of cancer-related genes on SS also are rare. The accumulation of rare transcript variants and the cytogenetic characters of SS are suggested to be necessary for assuming a genetic diagnosis of SS.

Congenital peripheral developing odontoma accompanied by congenital teratomatous fibroma in a 9-month-old boy: a case report.

Peripheral odontoma is rare, and only two cases of congenital peripheral odontoma have been reported. Congenital oral fibroma is also rare. We describe a unique case of congenital peripheral developing odontoma accompanied by congenital teratomatous fibroma in an infant. Both tumors were difficult to detect on radiography. Two small masses were seen in the median anterior portion of the palatal mucosa of a 9-month-old boy. The masses had been present since birth and were surgically removed at age 28 months, when one of the masses had grown to a diameter of 8 mm. Histopathologic examination showed a fibrous lesion and a tooth germ-like rounded lesion composed of dental papilla, enamel organ, dentin, and cementum. Although congenital odontoma is rare, it should be considered when selecting appropriate treatment, as early radiographic detection is difficult.