Due to the insensitivity of the petrous bone to expansile changes, lesions can remain latent in the petrous apex for many years, making early diagnosis challenging. Recognition often occurs only when damage to the seventh (facial) and eighth (vestibulocochlear) cranial nerves becomes evident. Clinical symptoms are primarily characterized by hearing loss and progressive facial paralysis. Hearing loss is typically sensorineural or retrocochlear due to involvement of the cochlea and cochlear nerve, while mixed hearing loss may occur if both the middle and inner ear are affected.
The cerebellopontine angle is the most common intracranial site for cholesteatomas. Symptoms often begin with trigeminal neuralgia (70%), accompanied by tinnitus and hearing loss on the affected side. In later stages, cerebellopontine angle syndrome may develop. Examination may reveal dysfunction of the fifth (trigeminal), seventh (facial), and eighth (vestibulocochlear) cranial nerves, manifesting as reduced facial sensation, facial muscle weakness, hearing loss, and ataxia.
CT imaging is helpful for assessing the extent of the lesion and destruction of critical structures, showing the lesion as a hypodense area. On MRI, the lesion appears as a sharply demarcated hypointense signal on T1-weighted imaging without enhancement, while it demonstrates intermediate or hyperintense signals on T2-weighted imaging. The DWI sequence of MRI has high sensitivity for distinguishing cholesteatomas. Differential diagnosis for petrous apex cholesteatomas and cerebellopontine angle cholesteatomas includes comparing with common tumors found in these respective regions.
Surgical treatment is the only effective approach, with the goal of complete lesion removal while maximizing preservation of surrounding anatomical structures. Surgical approaches include translabyrinthine and transcochlear approaches, middle cranial fossa approach, infralabyrinthine approach, infracochlear approach, retrosigmoid approach, trans-sphenoidal approach, and combined approaches.