Solitary plasmacytoma of bone is extremely rare in the jaw and most frequently arises in vertebrae and the skull. We report a case of solitary plasmacytoma arising in the mandible. A 67-year-old woman was referred to our hospital because of a slowly developing swelling in the right cheek. Intraoral examination disclosed a diffuse swelling in the right retromolar region. The patient did not have any pain or numbness. Panoramic radiography and computed tomography showed an osteolytic lesion measuring 20 × 15 mm in the right mandibular ramus. Laboratory analysis of the patient's blood and urine did not indicate any remarkable data. An incisional biopsy was performed with the patient under general anesthesia. The histopathological examination confirmed the diagnosis of plasmacytoma, predominantly IgA- λ type. Because there were no abnormal findings on bone marrow aspiration, the patient received local radiotherapy with a total dose of 50 Gy (in daily fractions of 2 Gy), and the tumor completely regressed. Seven years after radiotherapy, the patient is still alive without signs of recurrence or progression to multiple myeloma.
