JUVENILE KERATIN INOCULATION INDUCES CHRONIC EAR PATHOLOGY

Objective: Human neonatal temporal bones frequently show the formation of granulation tissue provoked by amniotic fluid keratin contents, de squamated keratinized epithelial cells and lanugo hair. Similar histop athologic findings have been produced previously in a short-term anima l model. To test the hypothesis that those short-term pathologic obser vations could have theoretical relevance for ear disease in older pati ents, a longer term animal model study was necessary. Methods: Into th e right bulla of 10 chinchilla pups was placed an aliquot of autogenou s, nonviable epidermal scrapings and hair. Into the left bulla was pla ced 1 mm(2) viable autogenous epidermal tissue. Animals were killed at intervals up to 11 months and then studied by light microscopy. Resul ts: Chronic ear histopathologic changes such as granulation tissue, os teoneogenesis, adhesions, and cholesteatoma were present. Over time, t hese secondary pathologic changes became more obvious than the initial keratin implant. Conclusions: The authors conclude that chronic patho logic changes resembling human ear disorders persist and that this mod el further extends the hypothesis that prenatally acquired keratin eve ntually could account for some cases of human ear disease.