Hyperostotic tympanic bone spicules in domestic and wild animal species
A. Heitmann, B. Parzefall, M. Zollner, A. Bruhschwein, W. Hermanns, A. Blutkehttps://doi.org/10.17221/8819-VETMEDCitation:Heitmann A., Parzefall B., Zollner M., Bruhschwein A., Hermanns W., Blutke A. (2016): Hyperostotic tympanic bone spicules in domestic and wild animal species. Veterinarni Medicina, 61: 187-194.
“Hyperostotic tympanic bone spicules” (HTBS), or “mucoperiosteal exostoses” (ME, syn.) are small, globular (≥ 1 mm in diameter), mostly stalked and drumstick-like, bony structures, which arise from the inner wall of the tympanic bulla and project into the middle ear cavity. HTBS present as mineral densities inside the tympanic bulla on radiographs or computed tomographic (CT) images. They have previously been referred to as “otoliths” and were thought to represent mineral concretions secondary to otitis media. Recently, it was shown that HTBS actually consist of regularly composed bone tissue, covered by normal middle ear mucosa. So far, HTBS have only extensively been described in dogs, where they occur with a prevalence of up to > 45%. A recent study detected ME, most likely representing HTBS, in the tympanic cavities of skeletonised skull bones of African lions. To estimate the occurrence of HTBS in other mammal species, the middle ears of adult animals of 78 different domestic, wild, and zoo species undergoing routine necropsy at the Institute of Veterinary Pathology of the LMU Munich, Germany were examined in the present study. HTBS were found in the tympanic bullae of carnivorous species, such as canids (wolf, fox), and in several large felid species (lion, tiger, leopard, cheetah). In contrast, HTBS were not present in domestic cats (more than to 200 cases), small carnivorous species such as mustelids, nor in any primate, ungulate, ruminant, pig, insectivore, or rodent species. The detectability of HTBS by CT of the tympanic bullae of large felids was demonstrated in an African lion. Histologically, HTBS consisted of mature lamellar bone, covered by periosteum and a partially ciliated, flat epithelium, regularly without any apparent inflammatory alterations. The present study demonstrates that HTBS may frequently occur in large felids and in different canid species. These findings should be taken into account when examining the middle ear, or interpreting bulla radiographs/CT-images of the respective species. However, the factors triggering the development of HTBS remain to be identified.Keywords:
exostosis; middle ear; mucoperiosteum; otolithReferences:
(1992): KNOWN CASE CONFERENCE. Veterinary Radiology <html_ent glyph="@amp;" ascii="&"/> Ultrasound, 33, 262-271 https://doi.org/10.1111/j.1740-8261.1992.tb00141.xNovales M., Ginel P. J., Diz A., Blanco B., Zafra R., Guerra R., Mozos E. (): Mucoperiosteal Exostoses in the Tympanic Bulla of African Lions (Panthera leo). Veterinary Pathology, , - https://doi.org/10.1177/0300985814531499Parzefall Birgit, Schmahl Wolfgang, Blutke Andreas, Baiker Kerstin, Matiasek Kaspar (2009): A rapid approach to ultrastructural evaluation and DNA analysis of the vestibular labyrinth and ganglion in dogs and cats. Journal of Neuroscience Methods, 177, 217-224 https://doi.org/10.1016/j.jneumeth.2008.10.003Parzefall Birgit, Rieger Alexandra, Volk Holger A., Maierl Johann, Brühschwein Andreas, Blutke Andreas (2015): PREVALENCE AND CHARACTERIZATION OF SMALL TYMPANIC BONE SPICULES AND DRUMSTICK-LIKE HYPEROSTOTIC TYMPANIC BONE SPICULES IN THE MIDDLE EAR CAVITY OF DOGS. Veterinary Radiology & Ultrasound, 56, 25-32 https://doi.org/10.1111/vru.12197Sula M. M., Njaa B. L., Payton M. E. (): Histologic Characterization of the Cat Middle Ear: In Sickness and in Health. Veterinary Pathology, , - https://doi.org/10.1177/0300985813511125Ziemer Lisa S., Schwarz Tobias, Sullivan Martin (2003): OTOLITHIASIS IN THREE DOGS. Veterinary Radiology <html_ent glyph="@amp;" ascii="&"/> Ultrasound, 44, 28-31 https://doi.org/10.1111/j.1740-8261.2003.tb01444.x