[A case of malignant mesenchymoma of the maxilla]

The case of a 48-year-old male with a malignant mesenchymoma of the maxilla is reported. The patient had complained of bloody rhinorrhea and cheek pain, and a total maxillectomy was performed. The tumor consisted of a rhabdomyosarcoma, an osteosarcoma and a chondrosarcoma, which were relatively differentiated. Later, recurrence of a tumor and a lung metastasis occurred, however the tumor revealed undifferentiated mesenchymal cells. This led us to suspect the origin of the malignant mesenchymoma had been a primitive mesenchymal cell. To our a knowledge, the present case is the first reported case of a malignant mesenchymoma with a maxillary origin in the world.