Hearing loss in Paget's disease: a temporal bone histopathology study.

BACKGROUND

Hearing loss in Paget's disease of bone (PDB) is typically mixed and bilateral. Although different mechanisms have been proposed, the pathophysiology of hearing impairment remains unclear.

OBJECTIVE

The purpose of this study is to describe the histopathologic findings of temporal bones in patients with PDB and elucidate possible pathologic mechanisms related to hearing impairment.

METHODS

This is an archival human temporal bone study of 8 subjects diagnosed with Paget's disease from the temporal bone collection of the UCL Ear Institute.

RESULTS

A fractured stapes footplate was observed in 1 temporal bone and stapes footplate fixation in 2 other specimens. Obliteration of Cotugno's canal by extensive bone remodeling was observed in 78% of temporal bones. An intracochlear vestibular schwannoma was observed in 1 specimen (previously reported in the literature). Other findings include microfissures and microfractures of the otic capsule, bleeding in the scalae, strial atrophy, and cystic lesions in the spiral ligament.

CONCLUSION

This study is the first to report a fractured stapes footplate, as a causative lesion of conductive hearing loss in PDB. Extensive bone remodeling around Cotugno canal also was a frequent finding, not reported before in the literature. We hypothesize that sensorineural hearing loss in patients with PDB of the temporal bone may, in some cases, be attributed to obliteration of Cotugno's canal by remodeling pagetoid bone, thus obstructing the venous drainage of the cochlea, with a subsequent effect on the function of stria vascularis and spiral ligament. This seems to be consistent with experimental studies in animals.