Bisphosphonate-associated osteonecrosis of the external auditory canal

Background: Osteonecrosis is a benign condition characterised by necrotic exposed bone, and is associated with bisphosphonate use. Osteonecrosis of the external auditory canal is rare, with only a few reported cases. Method: Two case reports of temporal bone osteonecrosis are presented. Results: A 64-year-old man with a history of immunoglobulin G kappa multiple myeloma developed a right external auditory canal ulcer 6 years after commencement on clodronate. A 72-year-old woman taking alendronate for osteoporosis, initially diagnosed and treated for right-sided otitis externa, was found to have underlying exposed bone in the right external auditory canal, with a computed tomography scan confirming destruction of the temporal bone. Conclusion: With increasing use of both oral and intravenous bisphosphonates in the community for benign conditions such as osteoporosis and for malignant conditions such as breast cancer and multiple myeloma, the diagnosis of bisphosphonate-associated osteonecrosis should always be considered in patients with a temporal bone lesion, and a relevant drug history taken.