title: Metaplasic bone tissue in tympanosclerosis.
abstract: Two different tissues have been observed in specimens of tympanosclerotic material studied under light and electron microscopy. The first, devoid of cells and blood vessels, is a dense fibrous tissue similar to that already described in fibrous tympanosclerosis. The second resembles a bone tissue, containing osteocytes and vascular channels; it is laid down by metaplasic fibroblasts following the invasion of the first tissue by osteoclasts and blood vessels after its calcification.
mesh_terms: D004432:Ear, Middle / Q000473:pathology*; D005347:Fibroblasts / Q000473:pathology; D006801:Humans; D008679:Metaplasia; D010010:Osteoclasts / Q000473:pathology; D012598:Sclerosis