A 35-year-old woman presents with progressive hearing loss over 6 months. Otoscopy shows a whitish, pearly lesion in the anterosuperior quadrant of the tympanic membrane. Weber test shows lateralization to the affected ear, and Rinne test shows bone conduction better than air conduction on the affected side. What is the most common cause of conductive hearing loss in this clinical presentation?

## Diagnosis: Cholesteatoma **Key Point:** A **whitish, pearly lesion** in the **anterosuperior (or posterosuperior/pars flaccida) quadrant** of the tympanic membrane with conductive hearing loss (Weber lateralizing to affected ear, Rinne BC > AC) is the classic presentation of **cholesteatoma** — an abnormal collection of keratinizing squamous epithelium in the middle ear. ### Why Cholesteatoma? | Feature | Cholesteatoma | Otosclerosis | TM Perforation | Cerumen Impaction | |---------|--------------|--------------|----------------|-------------------| | **Otoscopic finding** | **Whitish, pearly lesion / keratin debris** | Normal TM (no visible lesion) | Visible hole in TM | Wax in canal | | **Location** | Pars flaccida (Shrapnell's membrane) / anterosuperior quadrant | N/A | Central or marginal | External canal | | **Hearing loss type** | Conductive (± sensorineural if cochlea eroded) | Conductive → mixed | Conductive | Conductive | | **Weber lateralization** | Toward affected ear | Toward affected ear | Toward affected ear | Toward affected ear | | **Rinne** | BC > AC on affected side | BC > AC on affected side | BC > AC on affected side | BC > AC on affected side | | **Pathognomonic feature** | Pearly white mass, foul discharge, bone erosion | Carhart's notch at 2 kHz; **normal TM** | Visible perforation | Wax plug | ### Pathophysiology 1. Retraction pocket or marginal perforation → ingrowth of keratinizing squamous epithelium into middle ear 2. Accumulating keratin debris forms the characteristic **pearly white mass** 3. Enzymatic bone erosion (collagenases, osteoclast activation) → ossicular chain destruction → **conductive hearing loss** 4. Can erode into cochlea/labyrinth → sensorineural component; facial nerve canal → facial palsy ### Why NOT Otosclerosis? Otosclerosis presents with **progressive conductive hearing loss in a young adult woman** but the tympanic membrane is **entirely normal** on otoscopy. There is NO visible lesion. The pathology is at the stapes footplate (oval window), invisible on otoscopy. The explanation's claim that an "anterosuperior quadrant lesion is classic for otosclerosis" is factually incorrect and contradicts standard ENT teaching (Scott-Brown's, Cummings). ### Management of Cholesteatoma - **Surgical excision** is the definitive treatment (mastoidectomy ± tympanoplasty) - Canal wall down (modified radical mastoidectomy) or canal wall up technique - Regular follow-up mandatory due to high recurrence rate (~10–15%) **Clinical Pearl:** Any **whitish, pearly, non-translucent mass** behind or at the tympanic membrane = **Cholesteatoma until proven otherwise**. It is locally destructive and must not be missed. [cite: Scott-Brown's Otolaryngology 8e, Ch 3.17; Cummings Otolaryngology 7e, Ch 139]