• A non-neoplastic mass of keratin-producing squamous EPITHELIUM, frequently occurring in the MENINGES; bones of the skull, and most commonly in the MIDDLE EAR and MASTOID region. Cholesteatoma can be congenital or acquired. Cholesteatoma is not a tumor nor is it associated with high CHOLESTEROL.
  NLM Medical Subject Headings
  U.S. National Library of Medicine, 2025
• A pathologic process characterized by the proliferation of keratinizing squamous epithelium resulting in the accumulation of keratin and cells in the middle ear and/or mastoid. It may be congenital or acquired. If left untreated, it may increase in size and destroy adjacent structures.
  NCI
  U.S. National Cancer Institute, 2021
• A squamous cyst that may contain cholesterol clefts and granulomatous inflammation. (INHAND)
  CDISC Terminology
  Clinical Data Interchange Standards Consortium (CDISC), 2021
• Cholesteatoma is a benign but potentially destructive growth consisting of keratinizing epithelium located in the middle ear and/or mastoid process. In cholesteatoma, a skin cyst grows into the middle ear and mastoid. The cyst is not cancerous but can erode tissue and cause destruction of the ear.
  Human Phenotype Ontology (HPO)
  The Human Phenotype Ontology Project, 2025
• Non-neoplastic keratinizing mass with stratified squamous epithelium, frequently occurring in the meninges, central nervous system, bones of the skull, and most commonly in the middle ear and mastoid region.
  CRISP Thesaurus
  National Institutes of Health, 2006
• A cholesteatoma consists of squamous epithelium that is trapped within the skull base and that can erode and destroy important structures within the temporal bone. Its potential for causing central nervous system (CNS) complications (eg, brain abscess, meningitis) makes it a potentially fatal lesion.
  Medscape
  WebMD, 2025
• Cholesteatoma is an abnormal growth of skin in the middle ear behind the eardrum. It can be congenital (present from birth), but it more commonly occurs as a complication of chronic ear infections. Individuals with this condition usually experience a painless discharge from the ear. Hearing loss, dizziness, and facial muscle paralysis...
  NIH Genetic and Rare Diseases
  National Center for Advancing Translational Sciences
• Cholesteatoma is defined as the presence of keratinizing squamous epithelium within the middle ear, or in other pneumatized areas of the temporal bone. This keratinizing epithelium exhibits independent growth, leading to expansion and to resorption of underlying bone. Focal erosion of external canal bone with accumulation of keratin is...
  Epocrates
  Athenahealth, Inc., 2019