Heterotopic ossification in chronic fibrosing otitis externa.

Acquired external auditory canal atresia is a rare complication of chronic inflammatory otitis, and is generally fibrous or soft tissue in nature. Here, we present the first reported case of heterotopic ossification within chronic fibrosing otitis externa in a 25-year-old male patient with a childhood history of granular myringitis and failed tympanoplasty. A calcified mass was demonstrated adjacent to the tympanic membrane on CT imaging, and surgical exploration revealed a cohesive bar of bone traversing the medial external auditory canal. Drill canaloplasty and split-thickness skin graft coverage of the lateral tympanic membrane resulted in an improvement in the pure tone average from 79 to 55 dB. As the treatment for chronic fibrosing otitis externa involves the surgical widening of the external auditory canal, we alert surgeons to the possibility of cohesive bone formation as a potential cause of navigational confusion and inadvertent over- or under-drilling of the canal stenosis.