## Most Common Site of Cholesteatoma Origin **Key Point:** The pars flaccida (attic region) is the most common site of primary cholesteatoma, accounting for approximately 80–90% of cases. ### Anatomical Basis The pars flaccida is the weakest part of the tympanic membrane, located between the anterior and posterior malleal folds. This region has: - Thinner fibrous layer - Reduced structural support - Greater susceptibility to retraction - Direct communication with the attic (epitympanic recess) ### Pathophysiology of Retraction Pocket Formation 1. Negative middle ear pressure (from Eustachian tube dysfunction) 2. Retraction of pars flaccida into attic 3. Accumulation of desquamated epithelium 4. Progressive erosion of ossicles and mastoid bone 5. Cholesteatoma formation ### Clinical Features of Attic Cholesteatoma - Posterosuperior perforation (may appear small or pinhole) - Foul-smelling discharge - Ossicular erosion (malleus, incus most common) - Mastoid bone erosion - Risk of facial nerve and labyrinthine erosion **High-Yield:** Attic cholesteatoma is the classic presentation in NEET PG — remember "pars flaccida = attic = primary cholesteatoma." ### Differential Sites (Less Common) | Site | Frequency | Clinical Note | |------|-----------|---------------| | Pars flaccida (attic) | 80–90% | Most common; primary type | | Pars tensa (posterosuperior) | 10–15% | Secondary cholesteatoma; large central perforation | | Sinus tympani | Rare | Difficult to access surgically | | Facial recess | Rare | Often residual after surgery | **Clinical Pearl:** A small posterosuperior perforation with foul discharge and bone erosion on imaging is pathognomonic for attic cholesteatoma until proven otherwise. [cite:Dhingra 8e Ch 9]
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