Argyrophilic nucleolar organizer regions in auditory meatal skin and middle ear cholesteatoma

Comparative silver-staining of argyrophilic nuclear organizer regions (AgNORs) was performed to study the proliferative activity of auditory meatal skin and middle ear cholesteatoma. AgNOR expression patterns were counted by standardized methods in two centres, Bochum and London, and mean numbers of dots per nucleus were calculated. Specimens of normal auditory meatal skin showed 1.54 dots/nucleus (n = 12) in the Bochum study, whereas cholesteatoma had 3.71 dots/nucleus (n = 21). In the London study normal meatal skin showed two dots/nucleus (n = 4), whereas acquired cholesteatoma (n = 8) gave a mean of 4.90 dots/nucleus and congenital cholesteatoma a mean of 4.70 dots/nucleus (n = 2). Our findings confirm the hyperproliferative state of middle ear cholesteatoma, suggest that the congenital variety of cholesteatoma may have a similar activity and indicate that AgNOR staining is a useful technique for assessing cellular proliferation in cholesteatoma and objectifying and quantifying its aggressive behaviour.