A 74-year-old man received radiotherapy and chemotherapy with vincristine, doxorubicin, and dexamethasone for a solitary plasmacytoma, which first arose in the ilium in 2006. In 2008, a solitary plasmacytoma of the rib was diagnosed, and the patient received radiotherapy and chemotherapy with melphalan, prednisolone, and thalidomide. In 2009, an extramedullary plasmacytoma of the stomach was diagnosed, and the patient underwent radiotherapy. Thereafter, plasmacytoma did not develop in any other part of the body. In 2010, the patient visited a local dental clinic because of mandibular gingival swelling. Panoramic radiography performed at the clinic showed a radiolucent image in the mandible. The patient was referred to our department and underwent a detailed medical examination to determine the treatment. During his first visit, a biopsy was performed, and the lesion was diagnosed as plasmacytoma. A general examination showed no evidence of multiple myeloma. He was transferred to the Internal Medicine Department of our hospital, where chemotherapy with melphalan and prednisolone was initiated. On completion of the second course of chemotherapy, the gingival swelling of the foretooth region of the mandible decreased, and the tumor disappeared. Approximately 1 year after the completion of chemotherapy, the patient did not show signs of plasmacytoma in the oral cavity or in any other part of the body.
