4.1.1 Tympanosclerosis
Tympanosclerosis, a common sequela of chronic otitis media, is
characterized by hyaline degeneration and the deposition of calcareous
plaques in the connective tissue of the fibrous layer of the tympanic
membrane and/or middle ear submucosa; it may result in local bone
metaplasia during its late stages of development.5 As
EC-LSC is essentially a form of heterotopic ossification; the resultant
osseous tissue features an external morphology and texture similar to
that of normal bone but – as revealed by pathological examination –
also possesses the pathological characteristics of internal osseous
structures and lacunae. Table 3 shows the differences between
tympanosclerosis and EC-LSC. In some cases, EC-LSC may co-exist with
tympanosclerosis. This is clearly demonstrated by the presence of
concomitant EC-LSC and tympanosclerosis in three of the seven patients
investigated in this study. The co-presentation posed a significant
challenge during surgical operations.