Oral focal mucinosis (OFM) is an oral disease analogous to cutaneous focal mucinosis that develops in the skin and is an extremely rare disease. We report a case of OFM that developed in the mandibular gingiva. The patient was a 75-year-old man who presented with a gingival mass in the region of the mandibular anterior teeth. The mass was an elastic firm, pedunculated mass measuring 30 × 25 mm, and the surface was covered with normal mucosa. Contrast-enhanced computed tomography showed a hypointense image with a homogenous internal consistency, which was not accompanied by a contrast effect. Tissue biopsy was performed twice and did not lead to a definitive diagnosis. Therefore, an excisional biopsy was performed with the patient under local anesthesia, and a histopathological diagnosis of OFM was obtained from the resected specimen. Relapse has not been occurred as of 37 months after resection.

Lipoma is the most common benign tumor of the oral cavity. However, it is extremely rare to encounter chondrolipoma, a histological variant of lipoma that includes mature cartilage tissue in the lipoma. In this article, we describe a case of chondrolipoma arising in the tongue. A 15-year-old girl visited our clinic because of an asymptomatic mass of the tongue. On examination a relatively firm, nonulcerated, yellowish mass 8 mm in diameter was found in the right lateral border of the tongue. The mass was excised with the patient under local anesthesia. Histopathologically, the specimen was composed of mature adipose tissue and cartilaginous tissue surrounded by abundant myxoid and fibrous tissue. There was no cell atypia or mitosis in the specimen. The histopathological diagnosis was chondrolipoma. There was no recurrence during 9 months of follow-up.

Dentinogenic ghost cell tumor is a locally invasive neoplasm that forms ameloblastoma-like epithelial islands associated with dyskeratosis of ghost cells and formation of atypical dentin. It is commonly found in the jawbone, and occurrence outside the jawbone is relatively rare. We report a case of peripheral dentinogenic ghost cell tumor that developed in the mandible. A 71-year-old woman noted a rough surface of the left mandibular gingiva in April 2010. Gradually, the mass increased in size, and she was referred to our department in October 2010. At initial presentation, there was a pedunculated mass measuring 25 × 17 × 16 mm arising in the gingiva of the left molar region of the mandible. The tumor subsequently underwent a biopsy for detailed histopathological examination, and ameloblastoma-like epithelial islands were noted. Hence, the tumor was diagnosed as a peripheral ameloblastoma and was subsequently resected with the patient under general anesthesia. The tumor tissue exhibited dyskeratosis of ghost cells and the formation of atypical dentin in ameloblastoma-like epithelial islands that were not initially observed in the biopsy specimen. Finally, we diagnosed the tumor to be a peripheral dentinogenic ghost cell tumor. There have been no signs of recurrence during follow-up as of 5 year after surgery.

Multiple myeloma (MM) is a malignant tumor of plasma cells and presents with various clinical symptoms, including hematopoietic disorder, osteolytic lesions, organ dysfunction, and susceptibility to infection. Furthermore, skeletal-related events (SREs) such as bone pain, pathological fractures, and hypercalcemia should be managed. We describe a case of pathological fracture of mandibular condyle considered to be a SRE of MM.

　A 59-year-old woman with MM visited our department because of disturbed mouth opening. Computed tomography showed bone resorption and a pathological fracture of the mandibular condyle. Chemotherapy with lenalidomide, bortezomib, and dexamethasone was conducted for MM. As for the mandibular fracture, physical therapy enabling return to the centric occlusal position was also performed. After 1 month, open bite and disturbance of mouth opening had improved. New bone formation at the osteolytic lesion of the mandibular condyle was confirmed 6 months after chemotherapy. Conservative physical therapy for SRE effectively improved the quality of life.

Vascular malformation frequently occurs in the head and neck region. It is an extremely rare entity in the buccal space and pterygopalatine fossa. In this report, we describe a case of venous malformations (VM) extending from the buccal space to pterygopalatine fossa. The patient was a 54-year-old woman who presented with nerve palsy of the right maxillary gingiva in the molar region as well as the right buccal mucosa. Contrast-enhanced computed tomography revealed a mass lesion extending from the right buccal space to the pterygopalatine fossa, which compressed the posterior wall of the maxillary sinus. Magnetic resonance imaging revealed hypointensity equivalent to that of muscle on T1-weighted images and lobulated hyperintensity on fat-suppressed T2-weighted images. The clinical and laboratory findings indicated a diagnosis of pleomorphic adenoma or schwannoma. Surgical excision was performed by a maxillary sinus approach with the patient under general anesthesia. Furthermore, the external carotid artery was visualized to provide for massive bleeding. VM was definitively diagnosed. The postoperative course was uneventful for 2 years after surgery, with no evidence of recurrence. No clinical studies have reported VM extending from the buccal space to pterygopalatine fossa in association with nerve palsy.

The present report describes our experience treating a patient who had an arteriovenous malformation (AVM) discovered because of abnormal bleeding during tooth extraction. The patient was a 35-year-old man who underwent extraction of the lower left third molar tooth, which was horizontally impacted. During extraction, abnormal bleeding occurred, and the patient he was transferred to our hospital because the bleeding could not be controlled. Contrast-enhanced computed tomography (CT) and 3-dimensional CT angiography revealed an AVM inside the left mandible. Transvenous embolization was performed. There was no further abnormal bleeding, the postoperative course was good, and the patient was discharged. Two months later, follow-up angiography was performed, and AVM resolution was confirmed.

We report a case of tooth loss and alveolar bone necrosis secondary to herpes zoster in the region innervated by the third branch of the trigeminal nerve. The patient was a 74-year-old man who was referred to our department with chief complaints of tooth loss and exposure of the alveolar bone in the left mandible. He had a history of herpes zoster of the trigeminal nerve and had spontaneous loss of the left mandibular second premolar and first molar approximately 2.5 months and 1.5 months before his first visit, respectively. Initial examination revealed exposure of the alveolar bone of the two affected teeth, with gingival swelling and flare. In addition, paresthesia was present in the region innervated by the third branch of the left trigeminal nerve, for which a dermatologist had prescribed vitamin B₁₂. Antibacterial treatment with local irrigation was performed after initial presentation. Five weeks after his first visit, we observed the elimination of a sequestrum. Currently, the exposed bone has disappeared, and the patient's disease course has been uneventful. The pathological diagnosis was bone necrosis associated with infection.

Mini-implants for orthodontic anchorage are commonly used for orthodontic treatment. Inflammation of periodontal ligaments, root damage, fractures, and loss of fixation have been reported as complications associated with mini-implants. Nevertheless, emphysema has not yet been reported. We report a case of emphysema caused by nose blowing after removal of mini-implants.

　A 43-year-old woman was referred to our hospital because of swelling of her right cheek. One day before, two mini-implants had been placed in her right maxillary molar region at another hospital. However, they were removed because of inadequate anchorage. Swelling of her right cheek suddenly occurred after nose blowing. Computed tomographic images revealed perforation of the right maxillary sinus and pneumatic spaces around the right eyeball, in the subcutaneous tissue of the right eyelid, as well as in the temporal, buccal, and cervical regions. The diagnosis was subcutaneous emphysema in the right side of the face and neck. The patient was given antibiotics for 1 week, and the symptoms of emphysema resolved. To prevent emphysema after the placement of mini-implants in the maxillary molar region, it is necessary to perform thorough preoperative examinations and to appropriately explain postoperative self-care to the patient.

Recently, Gardner's syndrome was included in familial adenomatous polyposis (FAP), which is known to cause substantial numbers of adenomas based on genetic research. A 22-year-old man had facial injury and was referred to our department for investigation of facial trauma. On the computed tomography, osteomas were seen in the head and jaw. Furthermore, his past history (odontoma, impacted tooth, and epidermal cyst) and family history suggested FAP. We consulted the Department of Gastrointestinal Medicine for examination, and he was given a diagnosis of FAP. Proctocolectomy and ileoanal canal anastomosis were performed, and the postoperative progress has been favorable.