A 30-year-old presents with persistent foul-smelling ear discharge and conductive hearing loss. Otoscopy shows a pearly white mass in the posterosuperior quadrant with an attic retraction pocket. CT temporal bone reveals a soft-tissue mass eroding the scutum and lateral attic wall with erosion of the long process of incus. Which microscopic layer of cholesteatoma matrix is directly responsible for bone erosion?
- A Granulation tissue in the perimatrix ✓
- B Keratin debris (desquamated dead cells)
- C Stratified squamous epithelium of the matrix itself
- D Cholesterol granulomas within the debris
Correct answer: A. Granulation tissue in the perimatrix
Explanation
Bone erosion in cholesteatoma is primarily mediated by enzymes (collagenase, matrix metalloproteinases) released from the granulation tissue and inflammatory cells in the perimatrix — the subepithelial connective tissue layer beneath the squamous matrix. The matrix epithelium itself proliferates, but the osteolytic activity is enzymatic and pressure-mediated from the perimatrix. Keratin debris provides a culture medium for bacteria. Cholesterol granulomas are 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.