External auditory canal cholesteatoma (EACC) is a chronic inflammatory disease caused by debridement of the external auditory canal, accumulation of cholesterol crystals, and encapsulation of epithelial masses from various causes, and is not a true tumor. EACC is a chronic inflammatory disease caused by debridement, accumulation of cholesterol crystals and encapsulation of epithelial masses. The specific pathogenesis is not clear, but common causes include ear trauma, foreign body, surgery or inflammation, which can destroy the integrity of the epithelium of the external auditory canal, causing the cell growth of the germinal layer to flourish, and the keratinized epithelium to shed and accumulate, and due to the narrowing of the external auditory canal, the discharge of the shed epithelium is hindered. The normal metabolism of the external ear skin is disrupted, and the hyperplasia and keratinization of the external ear skin is disrupted. EACC is classified according to the clinical course of the disease, including congenital, traumatic, medical, spontaneous, obstructive, and infectious. According to Holt’s staging method, EACC is classified into 3 stages: stage I, with no or mild enlargement and no destruction of the tympanic membrane; stage II, with localized pouch formation, significant enlargement and severe bone destruction; and stage III, with invasion of the mastoid process and superior tympanic chamber. Clinical manifestations Clinical manifestations occur mostly in adults, with equal incidence in men and women, unilaterally, and can invade both ears. Small cholesteatomas without secondary infection may have no obvious symptoms. In larger cholesteatomas, a feeling of blockage in the ear, progressive conductive hearing loss, and tinnitus may occur. If secondary infection occurs, there may be ear pain, headache, and discharge from the external ear canal with a foul odor. On examination, a white or yellow cholesteatoma may block the deep part of the external auditory canal and its surface is covered with multiple layers of scaly material. In larger cholesteatomas, destruction and resorption of the osseous tract of the external auditory canal and significant enlargement of the osseous segment of the external auditory canal are seen after removal. The tympanic membrane is intact and may be congested and invaginated. Huge external auditory canal cholesteatomas may destroy the posterior wall of the external auditory canal and invade the mastoid, extensively destroying the mastoid bone and complicating cholesteatoma-type middle ear mastoiditis, which may also cause peripheral facial amplification. Diagnosis is based on the history and the presence of characteristic white cholesteatoma masses in the external auditory canal, and the diagnosis can be confirmed by removing the cholesteatoma for pathological examination. It is important to differentiate it from cholesteatoma of the middle ear, carcinoma of the external auditory canal, and necrotizing otitis externa. It is easily confused with otitis externa, external ear canal cerumen and cholesteatoma otitis media, and is often missed or misdiagnosed. To further clarify the staging, a CT scan of the temporal bone should be performed to understand the size of the soft tissue shadow of the external auditory canal, the presence or absence of bone destruction and the extent of destruction. CT scan and pathological examination can confirm the diagnosis. Treatment The aggressive nature of the biological behavior of external auditory canal cholesteatoma determines the importance of early diagnosis and early treatment. Early and complete removal of the lesion, complete removal of cholesteatoma and dead bone, and prevention of residual cholesteatoma and recurrence are the only means to eradicate the disease and prevent complications. Postoperative follow-up should be observed to remove residual or regenerated cholesteatoma. Early treatment and therapeutic approaches are important to reduce the resorption of bone in the external auditory canal and later recovery of hearing. The current treatment for EACC is removal of cholesteatoma, anti-infection, scraping of granulation, external auditory canal shaping, modified mastoid radical treatment or mastoid radical treatment. If there is external canal stenosis, external otolaryngoplasty can be performed at the same time. If the facial nerve is invaded by cholesteatoma and facial palsy occurs, the epithelium of the cholesteatoma should be carefully separated from the outer membrane of the facial nerve and the nerve should be covered with fascia during surgery. If there is a significant disruption of the auditory chain, reconstruction of the auditory chain is required.