Odontogenic myxoma is a relatively rare lesion in the oral and maxillofacial region, and it is a locally invasive tumor. We report a case of odontogenic myxoma that extended into the maxillary sinus in a child who was successfully treated by extirpation and curettage. A 12-year-old girl complained of a swelling in the left cheek region. An elastic-hard swelling measuring approximately 40 × 50 mm was found in the left maxillary region. The clinical diagnosis was an odontogenic myxoma of the left maxillary region. Radiographic and computed tomographic examinations showed an aggressive tumor widely extending into the maxillary sinus and left palatal region, with partial radiopacity in the central region. A pathological diagnosis of odontogenic myxoma was made on a biopsy examination. We extirpated the lesion and performed curettage with the patient under general anesthesia. The patient has had no sign of recurrence for 53 months.
