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MRONJ Staging — MFDS Part 1 MCQ

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HardHuman DiseaseMRONJ StagingMFDS Part 1

A 68-year-old woman receiving intravenous zoledronic acid for metastatic breast cancer has had an intraoral fistula probing to mandibular bone for 10 weeks. The surrounding mucosa is painful and erythematous, but there is no purulent discharge. Imaging shows that the disease is confined to the alveolar bone, with no pathological fracture, extraoral fistula, oroantral or oronasal communication, or osteolysis extending to the inferior mandibular border. She has no history of jaw radiotherapy or metastatic disease involving the jaw. According to the AAOMS staging system, how should this presentation be classified?

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Correct answer: E — Stage 2 medication-related osteonecrosis of the jaw

This is **Stage 2 MRONJ**. The fistula has probed to bone for more than 8 weeks and is associated with pain and erythema, indicating infection. Purulent drainage is not required: Stage 2 may occur with or without it. Stage 1 also involves exposed necrotic bone or a fistula probing to bone, but the patient must be asymptomatic and have no evidence of infection. Stage 3 requires additional advanced features, such as extension beyond the alveolar bone, pathological fracture, extraoral fistula, oroantral or oronasal communication, or extensive osteolysis; these are specifically absent. Stage 0 has no clinically exposed or probeable necrotic bone, while the at-risk category has no apparent necrotic bone.

Reference: Faculty of Dental Surgery, Royal College of Surgeons of England. The Oral & Dental Management of Patients Before, During and After Cancer Therapy, section 5.14: Medication related osteonecrosis of the jaw. February 2026. https://www.rcseng.ac.uk/-/media/Files/RCS/FDS/Publications/The-oral-and-dental-management-of-patients-before-during-and-after-cancer-therapy.pdf