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Objective: We report a rare case of salivary duct carcinoma possibly arising from the malignant component of carcinoma ex pleomorphic adenoma. Methods: A 56-year-old Japanese male complained of swelling in the left side of jaw for 2 years which was painless until 2 days ago. On extraoral examination, the face was bilaterally asymmetrical. An ultrasonography revealed hypoechoic mass of size 1.5x2.5x2.5 cm on left parotid gland. Computed tomography (CT) revealed a slight irregular mass on left parotid gland with no infiltration to adjacent tissues. Based on these findings, a clinical diagnosis of left parotid benign tumor was made. Results: A surgical excision was performed under general anesthesia. On histopathological examination, the connective tissue was rich in fibrous components and was accompanied by hyaline. Epithelial cells with high atypia proliferating invasively as cords into connective tissue were observed. The intraductal component had Roman-bridge-like architecture with central portion undergoing comedonecrosis. Based on these findings, a final diagnosis of salivary duct carcinoma possibly arising from pleomorphic adenoma was made. p16 hypermethylation is a known phenomenon in oral malignancy. We also checked the methylation status of p16 gene and found high level of methylation in this tumor. Conclusion: We reported a rare case of salivary duct carcinoma possibly arising from pleomorphic adenoma and also demonstrated high methylation level of p16 gene in the tumor.

In digital intraoral radiography (DIR), images with defects caused by the digital process are sometimes produced. Hence, we analyzed DIR images with defects taken using the photostimulable phosphor (PSP) plate method and then classified these images based on the causes of the defect. The aim of this study was to classify defects in DIR using the PSP plate system, and to discuss the causes of each type of defect and the methods that can prevent their occurrence.Images with defects due to the two PSP plate systems (Arcana and Arcana Mira) were selected and classified according to the defect. Image defects caused by geometrical techniques that occur in both the film and PSP plate methods were excluded from this study. Moreover, changes in the rate of occurrence of images with defects over time were analyzed in this study.The defects in images obtained by the PSP plate system were classified into six types, which were further divided into those caused by machine error or human error. Both types of error could influence the diagnostic performance. Machine error accidentally and rarely occurred; thus, the prevention of such errors is difficult. However, human error, especially errors caused by photo-induced discharge, could be prevented using appropriate measures.In DIR systems using the PSP plate method, human error should be prevented by education and training to improve operation.

BackgroundClavicle fractures (CF) after radical neck dissection (RND) for oral cancer are rare but are thought to occur as a result of myotonia and decreased blood supply to the muscles around the clavicle after RND. The current report presents a rare case of a non-neoplastic pathological CF after RND, and discusses the role of imaging examinations for the timely detection of CF.Case reportAn 82-year-old Japanese man underwent RND followed by chemotherapy without radiotherapy for secondary metastasis of the right cervical lymph node after resection of tongue cancer. Computed tomography at 6 months after RND revealed a fracture with bone destruction in the proximal end of the right clavicle. He had no history of trauma at the site of the fracture and no symptoms. The possibility of bone metastasis of the clavicle was considered; however, the bone destruction had not advanced 6 years after the discovery of the fracture. The CF was thus finally considered to be a side effect of RND, rather than metastasis.ConclusionCF is a rare complication following treatment for head and neck cancer but can be caused by neck dissection. Regular imaging examinations, including the clavicular region, are therefore needed before and after surgery to ensure the timely detection of CF.

Highlights • MMTAH is a new clinical entity, misdiagnosed as temporomandibular joint disorder. • MMTAH is diagnosed based on a square mandible, cord-like masseter muscle aponeurosis, and limited mouth-opening. • Aponeurectomy combined with coronoidectomy is the treatment of choice for a better prognosis. • It is important to evaluate the patient’s compliance with mouth-opening training before surgery., Introduction Masticatory muscle tendon-aponeurosis hyperplasia (MMTAH) is a new clinical entity that presents mainly with trismus due to hyperplasia of the masseter aponeurosis and temporalis muscle tendon. However, the etiological factors of this disease are unknown; it is often mistreated as temporomandibular joint disorder (TMD). Presentation of case We report a 32-year-old female patient complaining of bilateral pain in her jaw and difficulty opening her mouth. She was first diagnosed as TMD and treated with a splint; however, her symptoms did not improve. Clinical examination revealed a square mandible, tenderness in the left and right temporalis muscles and masseter muscles, and tenderness along the anterior border of the masseter muscle. Her maximum mouth-opening was 30 mm. Short TI inversion recovery magnetic resonance imaging showed areas of low intensity at the anterior border of the masseter muscle and around the coronoid process where the temporalis muscle tendon attaches. Consequently, the diagnosis made based on the clinical and radiographic findings was MMTAH. Bilateral coronoidectomy was performed, followed by a rehabilitation program for six months. The maximum opening was maintained at 48 mm two years after the operation. Discussion MMTAH was treated as type 1 TMD until it was recognized as a new disease at the conference for the Japanese Society for Oral and Maxillofacial Surgeons. Since then, many clinicians have become aware of this particular condition, and different treatment modalities have been proposed. Conclusion Clinicians should consider MMTAH as a differential diagnosis when the patient’s chief complaint is gradually decreasing mouth-opening.

エプーリスは慢性的な刺激や炎症によって歯肉に発生する反応性の増殖物である。右側上顎歯肉部に発生した巨大なエプーリスの1例を経験したので報告する。患者は42歳男性で，右側上顎歯肉の腫脹を主訴に当科を受診した。当科受診の約4か月前より右側上顎歯肉部の腫瘤を自覚した。その後数回にわたり腫瘤からの出血を認めたため近医にて止血処置を受けていた。口腔内所見では右側上顎に境界明瞭な弾性やや硬の，有茎性の腫瘤を認めた。CT所見では内部に骨様のX線不透過像を有し，右側上顎歯肉から増生する腫瘤を認めた。全身麻酔下に腫瘍切除術を施行した。摘出標本は70×50×28mm大であった。病理組織学的診断は骨形成性エプーリスであった。術後3年3か月を経過した現在，再発の兆候はなく経過は良好である。

This study obtained highly uniform and efficient GaN-based vertical-cavity surface-emitting lasers with curved mirrors from a single wafer. The average threshold current (I th) and the optical output power (P max) of 14 chips measured up to 7.0 mA were 0.64 mA and 4.5 mW, respectively. The standard deviations of I th and P max were 6.7% and 5.1%, respectively. Additionally, the best chip showed maximum values of wall plug efficiency and output power of 13.4% and 7.6 mW, respectively, at 5.2 mA and 12.8 mA operating currents.

We reported an extremely rare case regarding intraosseous clear cell variant of mucoepidermoid carcinoma in maxilla.

A single cavity filtering mirror with a highly varying reflectivity spectrum was used to demonstrate a single longitudinal mode operation for a VCSEL with a ∼25 μm cavity length. The 443.5 nm lasing peak had an SMSR of 42 dB at 9 mA, 70 kA cm−2. Increasing the number of DBR pairs between the VCSEL and filtering mirror cavity reduced the simulated optical standing wave in the mirror cavity by 57% and experimentally gave a 42% increase in the slope efficiency to achieve 2.56 mW at 7 mA from a device with a 4 μm aperture with a single longitudinal mode.

Clear cell carcinoma (CCC) is a rare malignant tumor that represents less than 1% of all malignant tumors in the salivary glands. The term CCC was officially defined in the fourth edition of the World Health Organization classification of salivary tumors in 2017. Herein, we report a case of CCC arising in the hard palate of an 85-year-old man. The lesion was clinically suspected to be salivary gland tumor, and was resected under general anesthesia. Histopathologically, the tumor consisted of clear cells containing diastase-digestive PAS-positive granules without mucin. Immunohistochemically, the tumor cells were positive for cytokeratin and epithelial membrane antigen, but did not react with myoepithelial differentiation markers. Additional imaging techniques (computed tomography, magnetic resonance imaging, and positron emission tomography) were used to examine the lesion. No metastatic lesions were observed in other regions of the body. Thus, based on the histopathological and immunohistochemical findings and the results of the imaging tests, the tumor was finally diagnosed as a CCC. No evidence of recurrence or metastasis was noted after surgery.

Adenomatous ductal proliferation/hyperplasia (ADP/H) is a rare hyperplastic condition of the salivary gland. It is mostly associated with other salivary gland pathologies such as tumors and inflammations, and is incidentally found in tissue sections during histopathological examinations of those diseases. Herein, we report a case of ADP/H in the parotid gland not associated with any other pathological lesions, and present a review of the literature on this condition. A 60-year-old Japanese female complained of swelling on the left side of parotid region. Clinical examination revealed a swelling on the lower lobe of the left parotid gland. The lesion was firm but non-tender and was not attached to adjacent structures. A clinical diagnosis of benign salivary gland tumor was reached, and surgical excision was performed under general anesthesia. Histopathological examination revealed an intact parotid gland capsule with isomorphic and basaloid cells within scanty cytoplasm. In addition, an admixture of hyperplasia and proliferation of the intercalated ducts, the presence of zymogen granules, the absence of solid nests, and a peripheral palisaded arrangement of the cells were observed. Based on these findings, a diagnosis of ADP/H was confirmed. ADP/H is a non-tumorous lesion; therefore, tumor involvement should be ruled out before the diagnosis is reached.

Introduction Elongated styloid process syndrome represents a group of symptoms, such as recurrent throat pain and neck pain, caused by elongation of the styloid process. We report a case of elongated styloid process syndrome with prolongation of the superior cornu of the thyroid cartilage. Case presentation A 50-year-old man was referred to our clinic with the chief complaint of discomfort on the right side of his neck. He had no history of any disease. Extraoral findings indicated pain during neck rotation. Computed tomography showed prolongation of the styloid process beyond the mandibular plane and close to the hyoid. Moreover, prolongation of the superior cornu of the thyroid cartilage was detected. The discomfort during rotation of the neck was due to the stimulation by the styloid process. Styloid resection was performed using the extraoral approach under general anesthesia. Conclusion Discomfort in the neck was resolved after operation., Highlights • Elongated styloid process syndrome represents a group of symptoms. • Morphological anomalies or deviations of the thyroid cartilage may cause swallowing discomfort. • Oral and extraoral methods are used as surgical techniques for styloid hyperplasia. • There have been no reports of styloid process prolongation with hypertrophic thyroid cartilage. • There are few reports concerning the prolongation of the superior cornu of the thyroid cartilage.

Introduction Mucoceles are mucous extravasation phenomena resulting from spontaneous ductal rupture or, less commonly, a traumatic cutting of a salivary excretory duct. Occasionally, the appearance of a mucocele closely resembles a neoplastic lesion, and it can be difficult to diagnose. Presentation of case A 74-year-old Japanese male patient was referred to our clinic with painless swelling related to the upper right canine-premolar area. Preoperative imaging of the lesion revealed that it was fluid-filled and the histopathological biopsy suggested a myxoid tumor. We excised the lesion with the patient under general anesthesia, using safety margins based on the histology of the biopsy specimen to reach the definitive diagnosis and treatment. The final pathological diagnosis was a mucocele in the vicinity with an aberrant small salivary gland. Follow-up visits showed complete healing of the epithelium, and no recurrence has been observed during the subsequent 30 months. Discussion In cases with a difficult definitive diagnosis based on medical history, diagnostic imaging and pathological examination, it is important to proceed carefully with the possibility of a tumor in mind. Conclusion This case emphasizes that some mucous cysts are challenging for clinicians in terms of diagnosis and treatment due to an uncommon presentation., Highlights • Mucoceles are relatively easily diagnosed with a clear clinical picture/history. • Mucocele often occurs on the lower lip due to frequent trauma from biting. • At an unusual site such as gingiva, it is likely to be diagnosed as a neoplasm. • We treated a maxillary gingiva mucocele initially diagnosed as a myxoid tumor.

Dental cone-beam computed tomography (CBCT) received regulatory approval in Japan in 2000 and has been widely used since being approved for coverage by the National Health Insurance system in 2012. This imaging technique allows dental practitioners to observe and diagnose lesions in the dental hard tissue in three dimensions (3D). When performing routine radiography, the examination must be justified, and optimal protection should be provided according to the ALARA (as low as reasonably achievable) principles laid down by the International Commission on Radiological Protection. Dental CBCT should be performed in such a way that the radiation exposure is minimized and the benefits to the patient are maximized. There is a growing demand for widespread access to cutting-edge health care through Japan’s universal health insurance system. However, at the same time, people want our limited human, material, and financial resources to be used efficiently while providing safe health care at the least possible cost to society. Japan’s aging population is expected to reach a peak in 2025, when most of the baby boomer generation will be aged 75 years or older. Comprehensive health care networks are needed to overcome these challenges. Against this background, we hope that this text will contribute to the nation’s oral health by encouraging efficient use of dental CBCT.

Epithelial–myoepithelial carcinoma (EMC) is a rare tumor constituting less than 1 % of all salivary gland tumors. This neoplasm most often involves the parotid glands, with less frequent involvement of the submandibular or minor salivary glands. This case report describes EMC arising from a minor salivary gland in the buccal mucosa. A 71-year-old Japanese man with a painless submucosal mass in the left buccal region was referred to our hospital. The patient stated that the tumor had been present for more than 4 years and was painless but increasing in size. Oral examination showed a mobile, well-defined mass of approximately 19 × 15 mm; its surface was covered mostly by normal mucosa. Magnetic resonance imaging showed a mass with well-defined borders and relative homogeneity internally. Incisional biopsy led to a histological diagnosis of a suspected pleomorphic adenoma or low-grade malignant tumor originating from the salivary gland. The patient underwent surgical excision under general anesthesia to obtain a definitive diagnosis, and EMC was diagnosed based on histopathological and immunohistochemical examination of the whole specimen. Because the surgical margins were positive in some areas, the patient underwent external postoperative radiotherapy (total of 60 Gy at 2 Gy/day). Recovery was uneventful, and good function returned after postoperative treatment. Four years after tumor resection and radiotherapy, no recurrence had been detected and no other lesions had developed.

Background Osteosarcoma, the most common primary bone malignancy, has an extremely poor prognosis and a high rate of local recurrence and distal metastases. Because osteosarcomas of the head and neck region are rare, accounting for less than 10% of all osteosarcoma cases, limited information is available about their treatment and prognosis. Because of the high rate of distal metastases associated with extragnathic osteosarcoma, surgery combined with chemotherapy is currently considered essential in its treatment. However, the role of chemotherapy has not been well elucidated in the treatment of head and neck osteosarcoma because of the rarity of this condition. Case presentation In this report, we present the case of a 58-year-old Japanese woman with osteosarcoma of the mandible that was treated with radical surgery combined with neoadjuvant and adjuvant chemotherapy. Because the tumor showed rapid growth during neoadjuvant chemotherapy, neoadjuvant chemotherapy was suspended and surgical resection was performed, followed by adjuvant chemotherapy. No evidence of local recurrence and distal metastasis was found 14 months after initial treatment. Local control is considered a principal prognostic factor for head and neck osteosarcoma. Conclusions Wide surgical excision should be considered a primary goal even during neoadjuvant chemotherapy, especially in cases that respond poorly to neoadjuvant chemotherapy.

The purpose of this study was to clarify the difference in diagnostic accuracy for alveolar bone defects of the mandibular molar region between cone-beam computed tomography (CBCT) and multidetector-row CT (MDCT) by receiver-operating characteristic (ROC) analysis. Artificial alveolar bone defects in a dry human mandible were scanned with a CBCT system (CB MercuRay; Hitachi Medical Corporation) and an MDCT scanner (Aquilion 16-slice; Toshiba Medical Systems Corporation). The field of view (FOV) for the CT images was 5, 10, and 15 cm. Five radiologists observed the obtained DICOM CT images using OsiriX version 3.8.1 (OsiriX Foundation) on an iMac computer (Apple Computer Inc.), and rated the confidence levels for detecting the bone defects using a continuously distributed test. The areas under the ROC curves (Az values) were then calculated with ROCKIT 1.1B (Charles E Metz, The University of Chicago). The significance of differences in the Az values between CBCT and MDCT was tested by the Steel–Dwass method with a significance level of 5 %. The overall differences in the Az values between CBCT and MDCT were not significant. However, in the images with 15-cm FOV, the Az value for CBCT was significantly lower than that for MDCT. The diagnostic accuracy for alveolar bone defects was comprehensively equal between CBCT and MDCT. In CBCT, a large FOV can be avoided to reduce the radiation exposure dose, because enlargement of the FOV does not improve the diagnostic accuracy.

The procedures of sialendoscopic sialolithectomy have been progressively developing for more than the last ten years. However, any procedures reported previously in the world, needed an incision of the papilla or duct wall of the salivary gland to insert the sialendoscope. Therefore, I developed three types of fine sialendoscope, which could be inserted into the duct without incision of the papilla or duct wall of the salivary gland. One is a sialendoscope of 1.1-mm outer-diameter(POLYDIAGNOST GmbH, Germany) with 6000-pixels optic fibers, and it has a working channel to insert an ultra fine basket forceps of 0.38-mm outer-diameter and an irrigation channel. Two is a sialendoscope of 1.2-mm outerdiameter(FiberTech Co., Ltd., Japan) with 1600-pixels optic fibers and a working channel. Three is a sialendoscope of 1.40-mm outer妖iameter (POLYDIAGNOST GmbH, Germany) with 3000-pixels optic fibers, and it has a working channel to insert a 1.9 Fr basket forceps (Boston Scientific Corporation, USA) or a 1.9 Fr probe of an electrohydraulic lithotripter AUTOLITH^[○!R] (Northgate Technologies Inc., Elgin, U.S.A.). Using these newly developed sialendoscope, I established a non-surgical endoscopic sialolithectomy system, and succeeded to remove the sialoliths of the submandibular gland safely and surely under the sialendoscopic observations with a minimal invasion.

Objective The objective of this study was to investigate the difference of the temporomandibular joint (TMJ) between deviated and nondeviated sides of the mandible in adult patients with mandibular deviation. Study design TMJ size, disk displacement, and clinical symptoms of 28 patients were examined clinically and by magnetic resonance imaging (MRI). Twelve age- and sex-matched control subjects were also used to evaluate which side of the mandible in patients was similar to the control. Results The TMJ on the deviated side showed a smaller condyle and a higher incidence of disk displacement than the nondeviated side and those in the controls. However, the clinical symptoms showed no differences between the deviated and nondeviated sides, and no association with disk displacement. Conclusions Our results suggest that the deviated side was the abnormal side and may have some association with mandibular deviation. However, the clinical symptoms could not indicate those differences.

Purpose The study goal was to clarify the association between computed tomography (CT) findings, histologic features, and outcome of osteosarcoma of the jaw (OSJ). Materials and methods The CT findings and histologic features of 10 patients with OSJ were retrospectively analyzed. The patients were histopathologically diagnosed to have OSJ. The points analyzed on the CT included the patterns of osteogenesis and any signs of bone destruction. The histologic types were classified according to the 1993 World Health Organization histologic classification of bone tumors. Furthermore, the histologic subtype was classified into the following 3 types: osteoblastic, chondroblastic, and fibroblastic. The grade of the tumor tissue was classified from I to IV. These were compared with the affected jaw site and the outcome of the patients with OSJ. Results All tumors were classified into the conventional central osteosarcoma histologically. Eight cases were osteoblastic, and 2 cases were chondroblastic. Grade I or II (4 of 5 patients are alive without disease) dominated in the maxilla, but in contrast, grade III or IV (4 of 5 patients are dead of disease or alive with disease) dominated in the mandible. A significant association was seen between the osteogenesis found on the CT images and the outcome, between the grade and the outcome, and between the outcome and the affected jaw site (P = .02), respectively, in OSJ in this study. However, no significant association was observed between the CT findings and the histologic features in OSJ in this series. Conclusions The osteogenesis on the CT, grade, and affected jaw site were considered to be prognostic factors in OSJ in this limited series.

Transcatheter arterial embolization (TAE) is an effective and minimally invasive treatment againstuncontrolled arterial bleeding. We report a traumatic aneurysm that occurred after tooth extraction and was treatedby TAE. A 48-year-old woman was referred to our hospital because of uncontrolled intraoral arterial bleeding 4days after third molar extraction. In her medical history, she had been treated for liver cirrhosis and hepatocellularcarcinoma. A pseudoaneurysm of the inferior alveolar artery was found on selective carotid angiography. Massive arterial bleeding from the aneurysm was successfully treated by TAE. TAE and selective carotid angiographywere useful for the management of hemorrhage probably caused by a traumatic aneurysm after toothextraction.

We present 3 cases of Sjögren's syndrome in which multiple sialolithiasis were observed in the parenchyma of the parotid gland. The sonographic examinations showed microliths that were observed as hyperechoic spots. Some of the microliths were accompanied with comet sign, however most of them showed no particular posterior echoes. None of them showed acoustic shadows, which are normally observed in cases with sialolithiasis. We were able to prove that some of the hyperechoic spots observed sonographically in patients with severe Sjögren's syndrome were microliths. Although these multiple microliths are rarely detected, they may exist potentially in higher frequency in patients with severe Sjögren's syndrome.

Neural networks are a new type of computing algorithm. They are especially useful in pattern recognition. In this study we applied neural networks to the prediction of lymph node metastasis of patients with oral cancer. A data set of 1,116 lymph nodes verified histopathologically was used to train and evaluate the neural networks. Various three-layer feed-forward networks with a back-propagation algorithm were employed in this study. Performance of the neural networks was compared with that of radiologists and discriminant analysis (Quantification theory type II). Neural networks had a sensitivity of 80.6% and a specificity of 94.6%. Diagnostic accuracy of the neural networks was 93.6%, which was comparable to those of discriminant analysis and clinical radiologists.

Objective We sought to clarify the correlation among a computed tomography (CT) or a panoramic radiography (PR) pattern of bone destruction, a histologic pattern of bone destruction, and a mode of invasion in carcinoma of the mandibular gingiva. Study design CT images, panoramic radiographs, and decalcified, hematoxylin-eosin–stained preparations of the excised mandibular bone of 62 patients with carcinoma of the mandibular gingiva were retrospectively evaluated. Each computed tomograph, panoramic radiograph, and the histologic pattern of bone destruction was classified as 1 of 5 types: erosive , erosive and partly mixed , mixed , mixed and partly invasive , or invasive . The mode of invasion of the tumor was also assessed with a hematoxylin-eosin–stained preparation of the initial biopsy specimen. The relationships among the CT pattern, the PR pattern, the histologic pattern of bone destruction, and the mode of invasion of the tumor were statistically analyzed by using the Spearman rank correlation test. Results The CT pattern ( P = .005) and the PR pattern ( P = .003) were significantly correlated with the histologic pattern with respect to the bone destruction. The CT pattern ( P = .996), the PR pattern ( P = .997), and the histologic pattern ( P = .521) of bone destruction were not correlated with the mode of invasion seen in the biopsy specimen. Conclusion The CT pattern and the PR pattern of bone destruction reflect the histologic pattern of bone destruction caused by carcinoma of the mandibular gingiva but are not associated with the mode of invasion of the tumor.