Oral myxoma usually arises in the jawbone and rarely occurs in soft tissue. A case of myxoma in the gingiva of the upper jaw is reported. The patient was a 75-year-old man, who had noticed a tumor in the right molar gingiva 40 years ago. The tumor became larger after extraction of an upper molar. A mushroom-shaped elastic hard tumor (20 × 20 × 15 mm) was noted in the upper molar gingiva. Radiographic and computed tomographic examinations showed a tumor in the maxilla, but extensive bone resorption was not observed. An incisional biopsy was done, and the diagnosis was myxoma. Partial maxillectomy including the tumor was performed with the patient under general anesthesia. Histopathological examination showed that the tumor was composed of spindle-shaped cells in a myxoid matrix. The tumor was situated mainly in the gingiva, but slight pressure-related bone resorption was observed on the surface of the alveolar bone. Four years after treatment, there was no evidence of recurrence.
