Rare Case of Rituximab Related Osteonecrosis of the Maxilla; A Case Report and Literature Review

Abstract Medication-related osteonecrosis of the jaw (MRONJ) is a known adverse effect of antiresorptive and antiangiogenic therapies. However, reports of osteonecrosis linked to rituximab, a CD20 targeting monoclonal antibody, are exceedingly rare. We present a unique case of extensive maxillary MRONJ in a male 38 years of age with a background of multiple sclerosis receiving rituximab therapy. An initial presentation of acute sinusitis, progressed to bilateral maxillary bone destruction despite conservative management, multiple surgical interventions, and hyperbaric oxygen therapy. No other established MRONJ risk factors were identified including anti-resorptive use, antiangiogenic use, dento-alveolar surgery or dento-alveolar trauma. The extent of destruction, reaching the orbit and cranial base, is unprecedented in rituximab related cases. This report adds to the growing literature on rituximab associated MRONJ and emphasizes the need for increased awareness and understanding of this monoclonal antibody being a potential risk factor for MRONJ.