Middle ear and inner ear tumors - benign / nonneoplastic

Topic Completed: 1 October 2013

Minor changes: 6 November 2019

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PubMed Search: Otosclerosis [title] review[ptyp]

Nat Pernick, M.D.
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Cite this page: Pernick N. Otosclerosis. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/earotosclerosis.html. Accessed August 8th, 2020.
Definition / general
  • Disorder of bone remodeling affecting bony labyrinth and stapes footplate
  • Does not appear to occur outside temporal bone (Am J Otol 1999;20:162)
  • Causes fixation of stapes footplate in oval window and inability to transmit sound waves manifesting as conductive hearing loss
  • Usually women; 50% have family history; begins in teenagers and slowly progresses
  • More common in whites than blacks, Asians or Native Americans
  • Associated with measles virus (Ann Otol Rhinol Laryngol 2001;110:897)
  • 85% bilateral
  • Stapedectomy (correction of fixation of footplate of stapes)
Gross description
  • Specimens are usually head and crura of stapes which are not affected by disease
Microscopic (histologic) description
  • Initially bone resorption and replacement by cellular fibrovascular tissue around blood vessels; then immature bone is deposited with continuous resorption and remodeling; over time, bone is deposited with increased collagen and reduced ground substance resulting in densely sclerotic bone with prominent cement lines
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