In acquired cholesteatoma formation, the most widely accepted pathogenetic mechanism (immigration/invagination theory) involves which pathological process?
- A Metaplasia of middle ear cuboidal epithelium into squamous epithelium due to chronic inflammation
- B Haematogenous seeding of squamous cells from a remote focus
- C Post-traumatic implantation of squamous cells following myringotomy
- D Retraction pocket formation at the pars flaccida with ingrowth of keratinising stratified squamous epithelium through the tympanic membrane defect into the middle ear ✓
Explanation
The most accepted theory of acquired cholesteatoma formation is the retraction pocket (invagination) theory: eustachian tube dysfunction causes persistent negative middle ear pressure, leading to retraction of the pars flaccida (Shrapnell's membrane) posterosuperiorly. This retraction pocket deepens progressively, and the keratinising stratified squamous epithelium accumulates desquamated keratin layers (keratin pearl) — creating the cholesteatoma matrix and sac. Other theories include epithelial immigration through perforation margins and basal cell hyperplasia, but retraction pocket pathogenesis is best supported by clinical evidence.
Reference: Dhingra Diseases of Ear, Nose and Throat, 7th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.