Denosumab-induced osteonecrosis of external auditory canal.

Denosumab is the world's first human monoclonal antibody for the treatment of osteoporosis and shares an active pathway with bisphosphonates, strongly suppressing osteoclast activities. This is the first case report describing a possible relationship between the development of osteonecrosis of external auditory canal and denosumab administration. We herein report an 81-year-old woman diagnosed with left osteonecrosis of external auditory canal who had a history of denosumab administration. She underwent left radical mastoidectomy due to being refractory to conservative treatment. No major complications or recurrence were observed in the left ear after surgery, but bone erosion in the right ear has continued to progress slowly despite the cessation of denosumab administration. Otolaryngologists should be aware of the association between osteonecrosis of external auditory canal and denosumab administration and consider performing long-term observation even after cessation.