## Distinguishing Congenital from Acquired Cholesteatoma ### Key Anatomical Difference **Key Point:** The hallmark of congenital cholesteatoma is the **presence of an intact tympanic membrane** with keratinous debris visible medial to it (in the middle ear space or mastoid). In contrast, acquired cholesteatoma is always associated with a **perforation or retraction pocket** in the tympanic membrane. ### Comparative Table | Feature | Congenital Cholesteatoma | Acquired Cholesteatoma | | --- | --- | --- | | **Tympanic Membrane** | Intact | Perforated or retracted | | **Pathogenesis** | Embryologic rest of squamous epithelium | Retraction pocket → invagination of epithelium | | **Age at Presentation** | Usually <40 years (often childhood/young adult) | Any age; often older children/adults | | **Otorrhea** | May be absent initially | Usually present and foul-smelling | | **Location** | Anterior to stapes, mesotympanum | Posterosuperior (attic) most common | | **Diagnosis** | CT/MRI; intact membrane is key clue | Clinical + imaging | ### Clinical Pearl **Clinical Pearl:** Congenital cholesteatoma is often discovered incidentally during evaluation for conductive hearing loss in a child with a **completely normal-looking tympanic membrane**. This is the critical discriminator — the membrane is NOT retracted or perforated. ### High-Yield Mnemonic **Mnemonic:** **INTACT = Congenital** (Intact tympanic membrane = Congenital cholesteatoma). If you see a hole or pocket, think **Acquired**. ### Pathophysiology Context Congenital cholesteatoma arises from embryologic remnants of squamous epithelium trapped during development (theory of epithelial rest). Acquired cholesteatoma develops secondary to chronic negative middle ear pressure → retraction pocket → epithelial invagination and keratinization. The intact membrane in congenital disease is therefore the single best discriminator. 
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