A case of chronic myelocytic leukemia with tumor formation in the mandible is presented. A 24-year-old female was referred to our department during hematological remission of chronic myelocytic leukemia because she complained of swelling of the mandibular region after suffering a contusion. The swelling was diagnosed to be caused by massive infiltration of leukemic cells by biopsy. Although the swelling macroscopically disappeared after chemotherapy for leukemia, the tumor was confirmed to persist by CT. She died about seven month after her first visit in spite of treatment.
