A cholesteatoma is defined histologically as:

• A A true neoplasm composed of cholesterol crystals and squamous metaplasia
• B Granulation tissue with cholesterol granuloma formation secondary to haemorrhage
• C Metaplastic columnar epithelium replacing the middle ear mucosa
• D Stratified squamous keratinizing epithelium in an ectopic location (middle ear/mastoid) with a fibrous matrix ✓

Explanation

Cholesteatoma is not a true neoplasm but a keratoma — stratified squamous keratinizing epithelium in an ectopic location (middle ear cleft or mastoid) surrounded by a fibrous stroma (the 'matrix'). The accumulation of desquamated keratin debris is the sac contents ('pars'). The matrix produces collagenases and cytokines that cause progressive bony erosion. It is not a true cholesterol-containing lesion (cholesterol granuloma is a separate entity).

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.