INTRODUCTION: We present the case of a patient with non-infectious osteomyelitis of the mandible, which is a recognized but unusual condition of unknown cause.

CASE PRESENTATION: A 14-year-old Caucasian girl presented with pain and edema in the left side of her jaw. A clinical examination led to a diagnosis of osteomyelitis and she was treated with antibiotics. Our patient continued antibiotic treatment for osteomyelitis and underwent decortication. Histology based on a biopsy showed new bone formation and chronic inflammation, and a diagnosis of sclerotic osteomyelitis was made. Over the next few years, she experienced pain on the left side of her jaw and increasing edema, and the size of the left side of her jaw bone increased. She was then sent to our Department of Medicine at the age of 16 years. Her symptoms included pain in the left side of her jaw that scored 4 on a visual analogue scale of 1 to 10. A diagnosis of bone disease was made based on bone scintigraphy and single photon emission computed tomography that showed hot spots in the affected left side of the jaw. Our patient was treated with a single dose of intravenous zoledronic acid (5mg) at age 17 years, which was repeated after 12 months. The bone pain was significantly reduced six months after treatment and had disappeared 24 months after treatment.

CONCLUSION: We report an unusual localization of non-infectious osteomyelitis of the jaw in a young woman. Even though the presentation was in the jaw, her condition improved after intravenous bisphosphonate treatment, as evaluated by reduced clinical symptoms, bone turnover evaluation as assessed by biochemical bone markers, and reduced activity on bone scintigraphy.