RESUMEN

INTRODUCTION: Medication-associated osteonecrosis of the jaws (MRONJ) is characterized by the presence of exposed bone or an intraoral or extraoral fistula in the maxillofacial region in patients with a history of treatment with anti-resorptive and anti-angiogenic drugs, such as monoclonal antibodies, and without a history of radiotherapy or metastatic diseases in the area. OBJECTIVE: The aim of this study is to report a case of a pathological mandibular fracture in an area of MRONJ in a patient diagnosed with Crohn's disease treated with infliximab. CASE REPORT: A 53-year-old male patient, an active smoker for 35 years, diagnosed with Crohn's disease, undergoing intravenous administration of infliximab 300 mg for 1 year and 3 months, with no previous history of anti-angiogenic or anti-resorptive medication, presenting with an extraoral fistula in the submandibular region for 4 months, with painful symptoms, diagnosed as MRONJ. He was initially treated conservatively, using antimicrobial photodynamic therapy (aPDT), antibiotic therapy, and the PENTO protocol. However, the patient evolved with a pathological fracture in the mandibular parasymphysis, requiring surgical reconstruction. FINAL CONSIDERATIONS: Pathological fracture of the mandible is a complication of MRONJ that compromises the patient's quality of life. The management of patients with MRONJ is complex and challenging.