Poster Presentation ESA-SRB-APEG-NZSE 2022

Two rare cases of osteonecrosis of the external ear canal associated with denosumab use for osteoporosis (#335)

Shejil Kumar 1 , Terry Diamond 1
  1. Endocrinology Department, St George Public Hospital, SYDNEY, New South Wales, Australia

Ear canal osteonecrosis (ECO) is a rare skeletal complication of antiresorptive use. We describe two patients who developed ECO whilst taking antiresorptives for post-menopausal osteoporosis; 1) a 79-year-old asymptomatic bisphosphonate-naïve woman with 2-year denosumab exposure with incidental findings of exposed bone in both ear canals whilst undergoing ear wax clearance, 2) a 64-year-old woman with right-sided otalgia after 5-years risedronate and 5-years denosumab treatment found to have an area of exposed bone in the right ear canal on otoscopy. Neither patient had previous local radiotherapy. In both patients, CT temporal bone scan found no evidence of bone erosion and bone turnover markers were suppressed. Both patients ceased denosumab and were managed conservatively with topical therapy, with stable otoscopy findings at 12-months with ongoing exposed bone.

ECO is considered to share similar pathogenesis to osteonecrosis of the jaw and has a working definition of exposed bone in the ear canal for >8 weeks without prior local radiotherapy. Twelve other cases have been reported in patients taking antiresorptives for osteoporosis. Bisphosphonates were implicated in 12/14 cases whilst two cases occurred in bisphosphonate-naïve patients on denosumab (including our case). Antiresorptive duration prior to symptom onset or diagnosis ranged between 1.5 years and >10 years (mean 6-7 years). Osteonecrosis was bilateral in 50% of cases and most common symptoms were otalgia (10/12), otorrhoea (5/12) and deafness (3/12). Our patient is the only one described with asymptomatic ECO. Treatment in almost all cases involved topical therapy initially and antiresorptive cessation. Outcomes are varied with some responding well to conservative therapy and others needing more extensive surgical treatment.

ECO is rare and can occur in patients taking bisphosphonates for osteoporosis and denosumab without prior bisphosphonate exposure. Localising ear symptoms in patients on antiresorptives should alert physicians to ECO and prompt early ear/nose/throat (ENT) surgical referral.

 

62f35b72412c5-ECO.png

  1. Abelardo E, Jaramillo M. Give ears some respite from regular microsuctioning in bisphosphonate-induced osteonecrosis of the external ear canal. J Laryngol Otol. 2022:1-3. doi: 10.1017/S0022215122000706.
  2. True HD, Ricks RG, Smith JA. Denosumab and bisphosphonate associated bilateral osteonecrosis of the external auditory canal. BMJ Case Rep;14:e241203. https://doi.org/10.1136/bcr-2020-241203.
  3. Takeda T, Ito T, Onishi I, et al. Denosumab-induced osteonecrosis of external auditory canal. Auris Nasus Larynx 48:1199-1203. https://doi.org/10.1016/j.anl.2020.07.007.
  4. Takahashi M, Yamamoto Y, Kuroyanagi H, et al. Bisphosphonate-associated ear canal osteonecrosis: a case report and review of the literature. Acta Oto-Laryngologica Case Reports 2:107-110.
  5. Thorsteinsson AL, Lomholt AF, Eiken P. Bisphosphonate-induced osteonecrosis of the external auditory canal: a case report. J ClinMed Case Reports 2:3.
  6. Wickham N, Crawford A, Carney AS, Goss AN. Bisphosphonate-associated osteonecrosis of the external auditory canal. J Laryng Otol 127 Suppl 2:S51-3. https://doi.org/10.1017/S002221511300100X.
  7. Kharazmi M, Hallberg P, Warfvinge G. Bisphosphonate-associated osteonecrosis of the external auditory canal. J Craniofac Surg 24:2218-20. https://doi.org/10.1136/bcr-2020-241203.
  8. Salzman R, Hoza J, Perina V, Starek I. Osteonecrosis of the external auditory canal associated with oral bisphosphonate therapy: case report and literature review. Otol Neurotol 34:209-13. https://doi.org/10.1097/mao.0b013e31827ca34d.