Regarding the pathogenesis of acquired cholesteatoma via the invagination theory, which of the following best describes the initial step?

• A Metaplastic transformation of middle ear respiratory epithelium into squamous epithelium
• B Direct implantation of squamous epithelium during traumatic perforation
• C Proliferative ingrowth of squamous epithelium through a marginal perforation
• D Eustachian tube dysfunction causing negative middle ear pressure with retraction of pars flaccida ✓

Explanation

The most widely accepted theory for acquired cholesteatoma pathogenesis is the invagination (retraction pocket) theory. Chronic Eustachian tube dysfunction leads to persistent negative middle ear pressure, causing the pars flaccida (which lacks an annular ring) to retract medially into the epitympanum forming a retraction pocket. Accumulating desquamated keratin debris unable to migrate normally forms the cholesteatoma sac. Other theories include metaplasia (Wendt), immigration through perforation, and basal cell hyperplasia.

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.