We report a case of venous malformation arising in the mandibular foramen area that was surgically removed through an extraoral approach. A 41-year-old woman experienced pain in the left side of the mandible for five years. At the time of initial examination, there was no swelling of the left cheek area or lymph nodes, nor any sensory abnormality in the area innervated by the mental nerve. Panoramic x-ray and CT showed a clearly demarcated, round, unilocular transmissive image in the mandibular foramen area of the left mandibular branch. MRI showed a low signal on T1-weighted imaging and a high signal on T2-weighted imaging. A venous malformation was suspected, and the tumor was resected via an extraoral approach with osteotomy of the lateral cortical bone of the mandibular ramus to ensure adequate visualization of the surgical field. The histopathological diagnosis was venous malformation. Postoperatively, there was temporary paresthesia in the area innervated by the left mental nerve and motor dysfunction in the area innervated by the marginal mandibular branch of the left facial nerve, however these symptoms gradually improved.

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　Malignant lymphomas occurring in HIV-infected patients are called HIV-related lymphoma (HRL), and their pathological and clinical features are different from those of HIV-uninfected patients. In this report, we describe a case of HRL involving the maxillary gingiva, with some discussion of the literature. The patient, a 44-year-old male, was referred to us with a chief complaint of swelling of the left maxillary gingiva. He had been diagnosed as HIV-infected via a positive HIV screening test at his previous hospital. Histopathological and immunohistochemical studies lead to a final diagnosis of high-grade B-cell lymphoma, NOS. The patient underwent four courses of antiretroviral therapy and CODOX-M/IVAC therapy by an immuno-infectious disease physician and a hematologist/oncologist, and the lesions in the maxillary gingiva disappeared. There was no relapse of HRL three years and eight months after the completion of chemotherapy.

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　Fatal arrhythmias are the most common cause of sudden death and can occur suddenly even in healthy adults with no history of heart disease. Brugada syndrome is one of the major fatal arrhythmias contributing to sudden death in young and middle-aged adults. It is impossible to detect all potential fatal arrhythmias before orthognathic surgery.

　We report a case of Brugada syndrome in which we observed IVF immediately after orthognathic surgery, performed defibrillation, and successfully resuscitated the patient. The patient was an 18-year-old male who was referred to our hospital with a chief complaint of mandibular retrusion. He was diagnosed with mandibular retrognathia, and simultaneous maxillomandibular advancement surgery and genioplasty were planned. During the initial consultation, it was revealed that the patient's grandfather had a history of heart bypass surgery and had died of unexplained cardiac arrest, but there was no significant medical history among the patient's parents. The patient himself had no history of palpitations or loss of consciousness. Preoperative ECG revealed sinus bradycardia. The anesthesiologist determined that surgery under general anesthesia was feasible, and the operation was performed. The surgery lasted 3 hours and 50 minutes, with a blood loss of 674 g. The surgery was completed without the occurrence of ventricular fibrillation. However, immediately after extubation, the patient experienced respiratory distress due to secretions and developed tachyarrhythmia. The tachycardia did not improve, and frequent ventricular fibrillation (VF) was observed, necessitating defibrillation. The VF did not reappear, and the patient was transferred to a general ward. However, on the third postoperative day, VF recurred, requiring defibrillation, and the patient was transferred to the ICU. On the 14th postoperative day, he was diagnosed with idiopathic ventricular fibrillation (IVF) by the cardiology department and had an implantable cardioverter-defibrillator (ICD) inserted.

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　Pleural metastasis is difficult to diagnose using chest CT or cytology from pleural effusion. We report a case of pleural metastasis from a mandibular gingival squamous cell carcinoma that required thoracoscopic biopsy due to pleural effusion that developed during postoperative chemoradiotherapy.

　The patient was a 72-year-old male who presented with a 45mm lesion on the left buccal gingiva and a palpable lymph node (major axis 30mm) in the left submandibular region. He was diagnosed with left mandibular gingival carcinoma (cT4aN2bM0, StageIVA) and underwent surgery under general anesthesia. During postoperative chemoradiotherapy for extranodal extension, the patient experienced right subcostal pain. A chest CT revealed pleural effusion confined to the right side, and thoracentesis was performed; however, the cytology was negative. Following the completion of chemotherapy, a thoracoscopic biopsy was performed, revealing pleural metastasis from oral squamous cell carcinoma.

　The patient was undergoing nivolumab therapy but developed immune-related adverse events, prompting a 2-month treatment interruption. During this time, the pleural lesions progressed, and his condition worsened, precluding further treatment. He transitioned to home care and passed away 11 months after diagnosis.

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　Kissing molars (KM) is a rare dental condition wherein two impacted molars in the lower jaw have their occlusal surfaces in contact, with their roots oriented in opposite directions and both crowns enclosed within a single follicular space.

　A 15-year-old male patient visited an orthodontic clinic with a chief complaint of delayed eruption of the right mandibular first and second molars. He was advised to undergo extraction of the right mandibular first molar and uprighting of the second molar. After the initial evaluation, the patient was referred to our department. Panoramic radiography and dental computed tomography (CT) images revealed that the right mandibular first and second molars were impacted, with their occlusal surfaces in contact and their roots oriented in opposite directions. A well-defined, unilocular, cyst-like radiolucent lesion was observed surrounding both crowns. The clinical diagnosis was complete impaction of the right mandibular first, second, and third molars. Given the patient's age, anterior open bite, and the complexity of extracting the first molar, we collaborated with an orthodontist to extract the right mandibular third molar, upright the second molar, and apply traction to the first molar. As a result, a good occlusal relationship was achieved.

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　Trafermin (genetically modified) preparation (brand name: REGROTH^® Dental Liquid Kit), a periodontal tissue regenerative medicine containing human basic fibroblast growth factor (bFGF), is widely used in dentistry in Japan. Although substantial evidence supports its efficacy, reports on adverse effects remain limited.

　A 44-year-old man presented to our hospital with painless swelling of the left cheek that had persisted for one year. He had previously undergone periodontal regenerative therapy with REGROTH^®. One month after surgery, he noticed a diffuse swelling in the left buccal region, which persisted without regression and remained as a mass-like lesion. Therefore, he visited our department one year postoperatively for further evaluation.

　Clinical examination revealed a painless, slightly soft mass with poor mobility near the inferior border of the mandible. Magnetic resonance imaging demonstrated a high-signal area on T1-weighted images and a low-signal area on T2-weighted images within the buccal space. Histopathological examination of the excised lesion confirmed adipocyte hyperplasia.

　Reports of adipose tissue-related adverse events following local administration of bFGF preparations – the main component of REGROTH^®– have occasionally been described in cosmetic surgery. This case suggests that adipocyte hyperplasia may develop in the buccal space after the use of REGROTH^®.

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　Inverted sinonasal papilloma (ISP) is a benign tumor originating from the maxillary sinus mucosa, which arises in the nasal cavity and paranasal sinuses and has a tendency for recurrence and potential malignant transformation. We report a rare case of ISP that extended from the maxillary sinus into the oral cavity following tooth extraction. The patient was a 61-year-old woman who developed an oroantral fistula after tooth extraction, through which part of the maxillary sinus tumor protruded into the oral cavity. A definitive diagnosis of ISP was made following CT and contrast-enhanced MRI examinations and a biopsy. Tumor resection based on the Caldwell–Luc procedure and closure of the oroantral fistula were performed under general anesthesia. One year after surgery, no recurrence has been observed, and the postoperative course remains favorable.

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　Metastatic tumors of the oral cavity are exceedingly rare. Matrix-producing carcinoma (MPC) is a rare subtype of breast cancer and, similar to other breast cancers, frequently recurs locally and metastasizes to the lungs or brain; however, no cases of oral cavity metastasis from MPC have been reported.

　We report a case of oral metastasis from MPC in a 59-year-old woman. The patient underwent a left mastectomy for MPC (pT2N0M0, Stage ⅡA), followed by adjuvant chemotherapy. During postoperative surveillance, multiple lung and brain metastases developed and were treated with systemic therapy, including immune checkpoint inhibitors. However, treatment was discontinued due to immune-related adverse events. Although oral mucositis improved with professional care, a mass subsequently appeared in the maxillary gingiva approximately three years after the initial surgery. Histopathological examinations confirmed oral metastasis of MPC. Palliative radiotherapy was administered; however, the lesion progressed, and the patient died two months after the diagnosis of oral metastasis.

　Oral metastatic tumors generally indicate advanced disease and poor prognosis. Appropriate oral care plays a crucial role in maintaining quality of life in patients with terminal cancer.

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　We report a case of gouty tophus arising in the temporomandibular joint (TMJ). A 77-year-old woman was referred to our hospital with a chief complaint of swelling and pain in the right TMJ. A cartilage-like bulge, swelling, and tenderness of the right TMJ, and trismus were observed. Panoramic radiography revealed a sclerotic bone lesion in the right mandibular condyle with a well-defined radiopaque area surrounding it, and CT showed a sclerotic lesion of the right mandibular condyle with surrounding calcifications. MRI revealed low signal intensity at T1W1 and T2W1 in and around the mandibular condyle. Preoperative blood tests showed a uric acid level of 4.5 mg/dL, which was within the normal range. A diagnosis of pseudogout in the right TMJ was suspected, and resection of the mandibular condyle and tumor was performed under general anesthesia. Postoperative histopathological examination revealed chalk-like rough tissue and large amounts of needle-shaped sodium urate crystals with strong polarization characteristics within the specimen, leading to a diagnosis of TMJ gout. Five years after surgery, no recurrence has been observed, and the maximum mouth opening has improved to 45 mm.

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　Pyoderma gangrenosum (PG), a refractory neutrophilic ulcerative skin disease, rarely affects the oral and maxillofacial region despite being a known extraintestinal manifestation of ulcerative colitis (UC). We report a case of an 18-year-old male with UC who developed PG secondary to an odontogenic infection. The patient initially presented with right buccal swelling and pain with poor oral hygiene. Antibiotics were prescribed for suspected odontogenic infection. Four days later, an extraoral fistula formed on his facial skin. Despite prolonged antibacterial therapy, tooth extraction, and debridement over a nine-month period, the buccal ulcer did not heal. In addition to the expanding cheek ulcer, the UC worsened with the appearance of subcutaneous abscesses in the occipital region and upper arms, and pulmonary nodules. Following the emergence of these systemic symptoms, corticosteroids were administered, leading to the rapid resolution of the skin ulcer and a therapeutic diagnosis of PG. Currently, his UC symptoms are controlled with corticosteroids and vedolizumab, and there has been no recurrence of skin lesions. This case suggested that bacterial infection and surgical intervention could act as pathergy, leading to the triggering of PG. Therefore, it is important for oral surgeons to recognize the pathophysiology of PG.

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