Which enzyme class, secreted by cholesteatoma matrix, is primarily responsible for the bone erosion seen in cholesteatoma?

• A Phospholipases
• B Matrix metalloproteinases (collagenases) ✓
• C Hyaluronidases
• D Elastases

Explanation

Matrix metalloproteinases (MMPs), particularly collagenases and gelatinases, are secreted by the cholesteatoma matrix keratinocytes and perimatrix cells. These enzymes degrade collagen and extracellular matrix, leading to osteoclast activation and bone erosion. Elevated MMPs (especially MMP-2, MMP-9) are found in cholesteatoma tissue compared to normal middle ear mucosa. This bone-eroding property underlies complications like labyrinthine fistula, tegmen erosion, and facial nerve involvement.

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.