Liposarcoma in the oral cavity is extremely rare, and dedifferentiated liposarcoma has seldom been reported in the oral region. No clear consensus has been established regarding the management of oral dedifferentiated liposarcoma.The case of a 28-year-old Japanese woman who presented with dedifferentiated liposarcoma in the maxillary gingiva is reported. She complained of swelling of the right maxillary gingiva, and swelling was evident in the region. No lymph nodes were palpable in either side of the neck. Incisional biopsy of the tumor region was performed, revealing dedifferentiated liposarcoma.The patient was treated with maxillectomy, and she has shown no clinical or radiological evidence of local recurrence or distant metastases as of 30 months after the end of treatment. This case provides a basis for the future appropriate management of oral cancer in patients with dedifferentiated liposarcoma. (c) 2017 Asian AOMS, ASOMP, JSOP, JSOMS, JSOM, and JAMI. Published by Elsevier Ltd. All rights reserved.