The matrix of cholesteatoma consists of which type of epithelium, and the perimatrix (lamina propria) contains which characteristic enzymatic activity responsible for bone erosion?
- A Columnar ciliated epithelium; lysozyme
- B Stratified squamous keratinising epithelium; collagenases and osteoclast-activating cytokines (IL-1, TNF-alpha) ✓
- C Transitional epithelium; alkaline phosphatase
- D Stratified squamous non-keratinising epithelium; hyaluronidase
Correct answer: B. Stratified squamous keratinising epithelium; collagenases and osteoclast-activating cytokines (IL-1, TNF-alpha)
Explanation
Cholesteatoma matrix is stratified squamous keratinising epithelium behaving like skin but trapped in an enclosed space. The perimatrix contains fibroblasts and inflammatory cells that secrete collagenases (matrix metalloproteinases) and bone-resorbing cytokines including IL-1, TNF-alpha, and prostaglandins that stimulate osteoclasts, leading to progressive bone erosion. This unique enzymatic milieu explains cholesteatoma's ability to erode ossicles, the tegmen, semicircular canals, and the facial canal.
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.