Presence of osteoclasts in middle ear cholesteatoma: a study of undecalcified bone sections

CONCLUSIONS: Osteoclasts are unlikely to be involved in bone resorption in middle ear cholesteatoma. OBJECTIVE: The authors searched for osteoclasts in undecalcified bone sections in patients with middle ear cholesteatoma to determine whether and to what extent these cells are involved in this disease. METHODS: Twelve patients, eight men and four women, aged 30-87 years, who underwent tympanomastoidectomy were enrolled. Six patients had primary acquired middle ear cholesteatoma (cholesteatoma group) and the other six patients had other otologic diseases including otosclerosis, non-cholesteatomatous chronic otitis media, adhesive otitis media, perilymphatic fistula and ossicular malformation (control group). The scutum bone was collected during surgery, fixed with ethanol, stained with Villanueva bone stain, and embedded in methyl methacrylate. Five-micrometer-thick sections were prepared and examined under a polarizing microscope. Images were analyzed using a semiautomatic graphics system. RESULTS: No osteoclasts were seen in any of the samples in either group. To avoid the risk of under-estimating the presence of osteoclasts, the number of osteoclasts was considered to be <1 in each sample, and the osteoclast density was calculated. The osteoclast densities in both the cholesteatoma and control groups were significantly lower than the sex- and age-matched standard value of the normal iliac cortical bone (p = .028).