Medication-related osteonecrosis of the upper jaw involving the zygomatic bone: A case report

Introduction and importance: Osteonecrosis of the jaw resulting from treatment with antiresorptive agents, such as bisphosphonates and denosumab, is widely recognized as medication-related osteonecrosis of the jaw (MRONJ). However, to the best of our knowledge, there are no reports of medication-related osteonecrosis of the upper jaw extending to the zygomatic bone.Case presentation: An 81-year-old woman treated with denosumab for multiple lung cancer bone metastases presented to the authors' hospital with a swelling in the upper jaw. Computed tomography showed osteolysis, periosteal reaction of the maxillary bone, maxillary sinusitis, and osteosclerosis of the zygomatic bone. The patient underwent conservative treatment; however, osteosclerosis of the zygomatic bone progressed to osteolysis.Clinical discussion: If the maxillary MRONJ extends to the surrounding bony structures, such as the orbit and skull base, serious complications may occur. Conclusion: It is important to detect early signs of maxillary MRONJ, before it involves the surrounding bones.