Clear cell odontogenic carcinoma (CCOC) was reclassified from a benign tumor to a malignant tumor by the WHO classification in 2005 because of its aggressive nature and potential for local recurrence and distant metastases. Only 81 well-documented cases have been reported to date to the best of our knowledge. A patient was referred to our clinic because of rapid swelling of the left side of the mandible. Computed tomography (CT) showed a bone defect in the mandible, but no cervical lymph node metastasis. We suspected a malignant tumor and performed a biopsy. We diagnosed CCOC of the left side of the mandible and performed segmental mandibulotomy. Histopathologically, the tumor consisted of clear cells containing diastase-digestive PAS-positive granules. Furthermore, immunohistochemistry showed that the tumor cells were immunoreactive for cytokeratins (CKs) 7, 17, 19, Ki-67 and vimentin, but non-reactive for CK20, smooth muscle actin (SMA), epithelial membrane antigen (EMA) and S-100 protein. The Ki-67 labeling index (LI) was 10%. We finally diagnosed CCOC. One year 5 months after surgery, the patient died of multiple organ failure caused by the multiple bone metastases. We discuss this rare case of multiple bone metastases developing from CCOC of the mandible and review the literature.

White sponge nevus is a rare condition that shows autosomal dominant inheritance and is characterized by edematous spongy white lesions, which cause thickening of the oral mucosa. Histopathological examination reveals thickening of the mucosal epithelium and vacuolation of the thorn cell layer, while no changes are detected in the basal layer.

　We encountered 3 patients (a 41-year-old mother and her 14-year-old and 12-year-old daughters) with familial white sponge nevus. The older daughter requested treatment for this condition and responded to long-term, low-dose macrolide therapy with clarithromycin. This report summarizes our experience with these patients.

Glomus tumor is a benign tumor derived from glomus cells found in the arteriovenous anastomosis in the vascular plexus of the skin and nail bed. Typically, it is a reddish purple and painful tumor with a predilection site for arising in the extremities, especially the nail bed. There are a few reports of the tumor arising in the oral region as well. Here, we report a case of a glomus tumor that developed in the palate.

　The patient was a 69-year-old woman who noticed a tumor in the left side of the palate around 2012, but left it untreated. In 2014, the mass gradually increased, and maladaptation of the denture occurred as a result of which she visited a local dentist. The patient was referred to our hospital for further examination.

　An elastic soft mass approximately 20 mm in diameter was discovered in the hard palate in the left maxillary molar region. Biopsy results led to the diagnosis of a glomus tumor. In December 2014, the palatal tumor was resected with the patient under general anesthesia. Five years after operation, no recurrence tendency has been noted, and the postoperative course is favorable.

Calcification of facial soft tissue is sometimes found in clinical X-rays, often associated with conditions such as sialolithiasis, tonsillolith, phlebolith, and calcifying epithelioma. We report the case of an ectopic calcification in the submandibular region that was found upon a traumatic event in a 78-year-old woman. She visited our hospital with the chief complaint of bleeding after facial trauma. Although facial CT showed no fracture line, we identified an ellipse radiopaque region measuring about 16 mm × 11 mm in the left submandibular subcutaneous tissue. Assuming that the radiopaque lesion was derived from ectopic calcification, we surgically removed the lesion with the patient under intravenous sedation. The margin of the specimen was easily discernable and was yellowish-white. Pathologically, the diffusely calcified body was surrounded by a thin fibrous capsule, which may have been an ectopic calcification due to a degenerated cyst. Nevertheless, identification of the primary disease was difficult. As of 1 year after the operation, there has been no evidence of recurrence in this patient.

Mucous cyst is caused by flow disturbances of saliva. The most frequent site is the lower lip, and cases involving the uvula are very rare. We describe a case of a mucous retention cyst on the uvula tip. A one-year-old boy was referred to the hospital because of a mass on the uvula tip. The mass measured 5 mm in diameter and was located on the right side on the uvula tip. Under a clinical diagnosis of a benign tumor, it was surgically enucleated. The mass was beneath mucous membrane and enucleated from the surrounding tissue. Histopathologically, the cystic lesion was lined by squamous epithelium, and a few minor salivary glands existed around the cyst. The diagnosis was a mucous retention cyst.