Published papers

Objective: Primary osteosarcoma of the jaw bones is very rare, and histological features of gnathic osteosarcoma remain obscure. The purpose of this study was to describe the clinicopathological features of gnathic osteosarcoma. Materials and methods: Seven cases of gnathic osteosarcoma from Japan diagnosed during the period between 2000 and 2016 were examined retrospectively. The histology of the surgical pathology materials was reviewed by two pathologists. Clinical information was obtained from the hospital's information system. Results: Of the seven cases, two patients had secondary osteosarcomas. As for the five cases of primary osteosarcoma, their ages ranged from 26 to 58 years (mean: 36.2, median: 28). Histologically, three cases were fibrotic tumors composed of spindle-shaped cells with mild to moderate nuclear atypia and the collagenous stroma accompanied by woven bones or mature lamellar-like bones. Two cases had cartilage formation. MDM2 and CDK4 expression was observed in two out of three cases on immunostaining. The histopathology of these three cases was regarded as the counterpart of low-grade osteosarcomas, namely, parosteal osteosarcoma and low-grade central osteosarcoma, arising in long bones. Conclusions: The surprisingly high incidence (60%, 3/5 cases) of low-grade osteosarcoma explains the reason why gnathic osteosarcomas present a more favorable prognosis than osteosarcomas arising in long bones. Furthermore, it provides insight into the tumorigenesis mechanism of low-grade osteosarcomas arising in the jaw and other sites.

Objectives: We aimed to evaluate the clinical value of an entire-circumferential intraoperative frozen section analysis (e-IFSA) for the complete resection of superficial squamous cell carcinoma (SCC) of the tongue. Materials and Methods: A total 276 specimens from 51 patients with pT1-2, N0, mucosal or submucosal invasion SCC were analyzed to evaluate the diagnostic accuracy of the e-IFSA and the added value of the e-IFSA to iodine staining. The e-IFSA results were compared with the final histologic results obtained using permanent sections. All specimens for the e-IFSA were taken over the entire circumference 5 mm outside from the iodine unstained areas. The outline of the main resected specimen after taking these outer mucosal specimens were defined as the surgical margins determined by iodine staining alone. Results: The e-IFSA results were in excellent agreement with final histological results (Cohen's kappa value: 0.85) and the e-IFSA showed high sensitivity (100%) and high negative predictive value (100%). The actual complete resection rate with an e-IFSA was 100% (51/51), and no patient required additional resection after surgery. In contrast, 10/51 patients (20%) patients showed residual atypical mucosal epithelium at or beyond the margin determined by iodine staining alone; this difference was statistically significant (P = 0.002). The 5-year local control rate and 5-year overall survival rate after this procedure were both 100%. Conclusion: An e-IFSA has additional value when performed in conjunction with iodine staining. An e-IFSA would be useful for achieving complete resection of superficial SCC of the tongue.

Although gingival reactive lesions such as pyogenic granulomas (PG) are fairly common in gingiva with natural teeth, their occurrence in association with dental implants is relatively rare. Additionally, these lesions are relatively small in size (10 mm). This case report presents a large PG observed in association with a dental implant and a systematic review of the literature on implant-associated PG. A 66-year-old woman presented at our department with a smooth, slightly red pedunculated lesion measuring 45 mm × 40 mm × 20 mm on the buccal and lingual gingiva surrounding the left mandibular second molar dental implant. Horizontal alveolar bone loss around the dental implant was observed on panoramic radiographs and cone-beam computed tomography. A biopsy was performed, and a histopathological diagnosis of PG was made. Complete resection of the lesion and curettage of the implant surface under local anesthesia was carried out. The patient exhibited no recurrence of PG after one year of follow-up.

Diffuse sclerosing osteomyelitis of the mandible (DSOM) is a nonsuppurative osteomyelitis mainly characterized by recurrent local mandibular swelling and pain. Because of the unknown pathophysiological mechanism underlying DSOM, treatment can be challenging. Reported treatment options include long-term analgesic medication, non-steroidal anti-inflammatory drugs (NSAIDs), antibiotics, corticosteroids, hyperbaric oxygen, and surgical treatment. However, these treatments cannot reliably lead to a long-lasting reduction of complaints. Recently, bisphosphonates has been reported effective in managing DSOM. We herein report a case of DSOM with a favorable response to a single infusion of zoledronate without prior treatment of other bisphosphonates. The patient was a 19-year-old woman who visited our hospital complaining of swelling and remarkable spontaneous pain in the right mandibular angle region. Under the diagnosis of osteomyelitis of the mandible, the clinical symptoms were improved by administering an antimicrobial agent and anti-inflammatory analgesic, but computed tomography (CT) showed exacerbation of bone resorption. A biopsy showed fibrosis between the bone tissue and trabeculae, a finding consistent with post-inflammatory changes. 99mTc scintigraphy showed an abnormal accumulation in the right mandibular ramus. Based on these results, she was diagnosed with DSOM. As a result of discussing with the physician in charge of internal medicine, it became the policy of the bisphosphonates and the intravenous administration of zoledronate 4 mg was enforced. Her bone sclerosis and bone resorption showed an improving trend on CT three months after the zoledronate administration, and there have been no symptoms or exacerbation of findings in three years since the administration.

The aim of this study was to clarify the clinical significance of bone metabolism in the mandibular condyles in determining condylar resorptive changes. Twelve condyles of patients with idiopathic condylar resorption and degenerative joint disease were analysed using 99mTc HMDP SPECT/CT at baseline and subsequent computed tomography during the follow-up period. Twenty-two healthy condyles were enrolled as controls. After generating three-dimensional SPECT/CT images, two independent observers scored the degree of condylar uptake and measured the morphological changes in the condylar height and condylar volume. In the group with positive condylar uptake, the follow-up computed tomography showed significant decreases in condylar height (−1.69 ± 0.93 mm) and condylar volume (−12.51 ± 10.30%) when compared to healthy controls (condylar height, 0.09 ± 0.54 mm; condylar volume, −0.29 ± 4.22%) (P < 0.001). Moreover, the degree of uptake correlated with the changes in condylar height (observer 1, P = 0.012; observer 2, P = 0.039) and condylar volume (observer 1, P = 0.005; observer 2, P = 0.037). These results suggest that condylar bone metabolism is closely related to the resorptive activity. Thus, SPECT/CT would be useful in the prognostic evaluation or determination of treatment strategies for idiopathic condylar resorption and degenerative joint disease.

© 2018 Asian AOMS(+) ASOMP(+) JSOP(+) JSOMS(+) JSOM(+) and JAMI Myelodysplastic syndrome is an acquired hematopoietic disorder showing symptoms of pre-leukemia and refractory anemia. In the tooth extraction process of such cases, bleeding tendency due to pancytopenia, infection etc., becomes a problem. As such, a cautious approach is required. We have confirmed platelet transfusion refractoriness prior to tooth extraction in a myelodysplastic syndrome patient, and hereby report a case of tooth extraction following human leukocyte antigen (HLA)-compatible concentrated platelet transfusion. The patient was a 55-year-old female who was examined at our department due to a request for the extraction of tooth No. 36. Following consultation at the Hematology Department, platelet transfusion was performed as a pretreatment upon hospitalization. Increased body temperature, chills, shivers, and feelings of discomfort in the pharynx were observed. A close examination was performed due to a lack of increase in platelet count, and revealed platelet transfusion refractoriness caused by anti-HLA antibodies. Therefore, the patient was re-hospitalized and transfused with a platelet concentrate-HLA preparation. One hour later, an increase in platelet count was confirmed and the tooth extraction was performed. There was no evidence of bleeding or infection following extraction, and the prognosis was good.

© 2019 Asian AOMS(+) ASOMP(+) JSOP(+) JSOMS(+) JSOM(+) and JAMI Spindle cell lipomas and pleomorphic lipomas are uncommon and distinct variants of benign lipomas. Although spindle cell lipomas and pleomorphic lipomas were originally considered different entities, the recent WHO classification defines them as spindle cell/pleomorphic lipoma (SCL/PL). This is because of their similar clinical features and the existence of intermediate histopathological features between them. A 77-year-old male presented to our clinic with a painless swelling on the left inferior border of the mandible. Computed tomography revealed a clearly defined mass in the subcutaneous lesion. With a histopathological diagnosis of myxolipoma, demonstrated by biopsy, excisional surgery was performed under general anesthesia. The histopathology revealed SCL/PL with the presence of spindle cells and mature adipocytes. No tumor recurrence had been noted at two year after surgery.

© 2019 The Author(s). Background: Calcium pyrophosphate dihydrate crystal deposition disease is a condition in which calcium pyrophosphate dihydrate crystal is deposited in joint cartilage and ligaments. Calcium pyrophosphate dihydrate crystal deposition disease that involves calcification around the odontoid process of the second cervical vertebra is called crowned dens syndrome. Crowned dens syndrome is accompanied by fever in addition to acute and intense neck, posterior head, and temporal pain; thus, distinguishing crowned dens syndrome may be difficult in the presence of odontogenic infection. To the best of our knowledge, this is the first report describing a patient with crowned dens syndrome with coexisting odontogenic infection. Case presentation: A 75-year-old Japanese woman was examined in the Emergency Department of this hospital due to a chief complaint of worsened buccal swelling on the left side. An odontogenic infection was considered, and she underwent her first examination. She presented with a body temperature of 37.4 °C, marked swelling and tenderness of her left lower eyelid through to her left cheek, and pain on the left temporal area. Blood tests revealed a leukocyte count of 6700/μL and a C-reactive protein level of 7.15 mg/dL. There was swelling and pain around the gingiva and acute purulent apical periodontitis of left maxillary second premolar. Cellulitis of the left cheek was diagnosed. After performing drainage of the pus, antibiotic treatment was initiated. Although her clinical symptoms improved, blood tests on day 9 of hospitalization revealed a leukocyte count of 6500/μL and a C-reactive protein level of 25.62 mg/dL, which were indicative of worsening symptoms. Computed tomography was performed to evaluate remote infection and images revealed a calcification around the odontoid process of her second cervical vertebra. When she was referred to the Orthopedic Surgery Department, pseudogout of the cervical spine was diagnosed. Subsequently, oral acetaminophen was initiated, and both her leukocyte count and C-reactive protein improved markedly. Conclusions: In the presence of persistent fever and abnormally high leukocyte and C-reactive protein indicative of an inflammatory reaction, coexistence of pseudogout should be considered. In particular, when symptoms of temporal pain are present, the possibility of pseudogout of the cervical spine must be considered in the differential diagnosis.

© 2019 European Association for Cranio-Maxillo-Facial Surgery Purpose: This study compared the diagnostic accuracy of jaw bone invasion (JBI) of oral cancer observed with three-dimensional (3D) SPECT/CT, CT, and MRI, and evaluated the clinical advantages of 3D SPECT/CT compared to conventional two-dimensional (2D) SPECT/CT. Materials and methods: From April 2014 to January 2018, consecutive 16 oral cancer patients with suspected JBI, who had preoperatively undergone the imaging tests, were retrospectively enrolled. The likelihood of JBI was independently scored by a radiologist and oral surgeon. Using 2D or 3D SPECT/CT images, 20 oral surgeons delineated virtual surgical areas on 3D-printed jaws for 3 cases in which the extent of JBI was fully pathologically confirmed. The surgeons completed questionnaires regarding surgical planning and explanations for patients using Likert scales. Results: JBI was found in 9 patients including 5 (56%) with initial bone invasion. 3D SPECT/CT showed very high negative predictive value (100%) and inter-observer agreement (kappa = 0.917). 3D SPECT/CT was more sensitive than CT and MRI when inconclusive findings for JBI were considered negative. Compared to 2D SPECT/CT, 3D SPECT/CT had greater clinical advantages such as surgical planning and explanation to patients (p < 0.005). Conclusion: 3D SPECT/CT is useful not only for detecting JBI but also for surgical planning.

© 2018 The Author(s). Background: Parosteal osteosarcomas are usually low-grade tumors, however, sometimes they transform to high-grade tumors, which is named dedifferentiation. This phenomenon has been reported in long bones. Recently, we encountered a patient with dedifferentiated parosteal osteosarcoma occurring in the maxilla. Here, we report a first case of dedifferentiated parosteal osteosarcoma of the head and neck region. Case presentation: A 45-year-old Japanese woman with a refractory bone lesion in the maxilla presented to our hospital. A biopsy showed atypical spindle cell proliferation involving dedifferentiated high-grade component, which was diagnosed as dedifferentiated parosteal osteosarcoma. Three cycles of neoadjuvant chemotherapy using ifosfamide and pirarubicin were performed followed by sub-total maxillectomy. Histopathological results showed that neoadjuvant chemotherapy was effective for high-grade component. The decision to perform adjuvant chemotherapy (cisplatin and pirarubicin) was made because distant metastasis has been reported, even in cases with dedifferentiated parosteal osteosarcoma in which complete necrosis of high-grade component was achieved due to neoadjuvant chemotherapy. There was no recurrence 15 months after surgery. Conclusions: Dedifferentiated parosteal osteosarcoma can occur in the head and neck region. Chemotherapy including anthracycline anticancer agent could be effective for high-grade component of dedifferentiated parosteal osteosarcoma.

© 2018, International & American Associations for Dental Research. This study investigated a case of spindle cell carcinoma (SpCC) in tongue pathological lesions. The patient experienced a local recurrence and distant metastasis after surgical intervention. Although standard chemotherapy was administered, a granulomatous mass continued to develop. This aggressive growth led to survival of the tumor. Secondary debulking surgery was performed to improve the patient’s quality of life at the request of the patient. Using a tissue sample derived from the secondary debulking surgery, we performed an analysis of the tumor’s cell surface antigens, differentiation potential, metastatic ability, and inhibition potential by anticancer reagents. In vitro analysis revealed that the cell population grown under adherent culture conditions expressed the mesenchymal stem cell (MSC) markers CD73, CD90, and CD105. The cell line established from this SpCC contained colony-forming unit fibroblasts (CFU-Fs) and exhibited multipotent differentiation into several mesenchymal lineages, including bone, cartilage, and fat. The SpCC cells also displayed vigorous mobilization. These characteristics suggested that they had the differentiation potential of mesenchymal cells, especially MSCs, rather than that of epithelial cells. The surgical specimen analyzed in this study resisted the molecular target reagent cetuximab, which is an epidermal growth factor receptor inhibitor. This clinical insight revealed that chemotherapy-resistant SpCC cells have different characteristics compared to most other cancer cells, which are sensitive to cetuximab. Our cell death assay revealed that SpCC cell death was induced by the anticancer drug imatinib, which is known to inhibit protein tyrosine kinase activity of ABL, platelet-derived growth factor receptor α (PDGFRα), and KIT. Here, we report recurrent SpCC with characteristics of MSCs and potential for treatment with imatinib.

Clear cell carcinoma (CCC) is a malignant neoplasm of epithelial origin classified in the 2017 World Health Organization (WHO) classification as a low-grade salivary gland tumor consisting of glycogen-rich clear cytoplasm. We report a case of a 34-year-old woman presented in our department following the complaint of a mass in her right retromolar area. The tumor measured 10-mm in diameter and was elastic and hard mass. Spontaneous pain or tenderness and desensitization of the tongue were not observed. Marginal resection of the mandible was performed under general anesthesia. The lesion was located in the minor salivary gland that is mainly composed of mucus glands and had a relatively clearly defined circular shape. However, there was no film fabrication in the surrounding resions. Additionally, atypical cells comprising a clear cytoplasm and irregularly shaped pyknotic nuclei were growing in sheet form or island form, and markedly hyalinized fascicles were observed between the alveolar walls of the atypical cells. Immunohistochemical stains revealed these tumor cells to be positive for epithelial cell markers but negative for myoepithelial ones. Considering the above findings, the tumor was diagnosed as CCC. The patient is currently free from disease 37 months after surgery.

Background: Microsurgery requires high skills for suturing using fragile threads, often within narrow surgical fields. Precise tension is required for good healing and to avoid the risk of thread breakage. Methods: To meet the demands, we developed a novel assist robot utilizing high-precision sensorless haptic technology. The robot adopts a cable-driven mechanism to maintain a distance from the surgical area and enhances compatibility with surgical equipment such as microscopes. The robot performance was verified through in vitro and in vivo experiments using a rat model. Results: The realization of precise tension control was confirmed in both experiments. In particular, in the in vivo experiments, the developed robot succeeded to produce a knot with an accurate tension of 0.66% error. Conclusions: The developed robot can realize to control traction force precisely. This technology might open up the window for a full assist robot for microsurgery with haptic feeling.

Objectives: The aim of this study was to assess a three-dimensional (3D) correlation between preoperative 3D bone single photon emission CT (SPECT)/CT, which allows the visualization of radiotracer uptake on 3D volume-rendered CT images, and histopathological characteristics in the medication-related osteonecrosis of the jaw (MRONJ). Methods: We conducted a full histopathological assessment of the resected jaws in four patients with Stage 2 or 3 MRONJ. The pathologic results were classified as follows: necrosis without any tissue vascularity (N + V-), necrosis with both vascularity and acute inflammatory cell infiltration due to bacterial infection (N + V+I+), necrosis with regenerative vasculature but no inflammatory cell infiltration (N + V+I-), and chronic inflammation without massive necrosis (N-V +I+). These classifications were correlated with imaging results. Results: The N + V- areas visually represented the area of necrotic bone exposed to the oral cavity and were consistent with defect area of radioisotope uptake in SPECT/CT. The N + Vareas were surrounded by the N + V+I + areas where increased radiotracer uptake was clearly seen. Also, abnormal uptake was found in both of the N + V+I- and N-V +I+ areas. The extensive surgical resections from necrotic core to bloody viable margins were performed in all cases, although one had the recurrence of MRONJ at the margin showing abnormal uptake that histologically represented the N + V+I- area. Conclusions: Radiologic-pathologic correlation of MRONJ could be achieved using 3D SPECT/CT. The presence of regenerative vascularity with necrosis or inflammation seemed to determine bone metabolism in MRONJ. The recurrence of MRONJ was observed in one case, and 3D SPECT/CT had preoperatively depicted the recurrence site.