The cranial nerves affected are (from most common to least common) : VIII (cochlear component), VIII (vestibular component), V

Acoustic neuroma/vestibular schwannoma
Meningioma, a tumor of the meninges or membranes that surround the nerves passing through the CPA
Cerebellar astrocytoma, a malignant tumor of star-shaped glial cells called astrocytes in the cerebellum
Intracranial epidermoid cyst
Lipoma
Glomus jugulare associated with the glossopharyngeal nerve
Idiopathic hypertrophic pachymeningitis
IgG4-related hypertrophic pachymeningitis
CPA Metastases in cancer patients with inner ear symptoms (rare)

Diagnosis
Radiography
Subsequent to diagnosis of sensorineural hearing loss, and differential diagnosis of retrocochlear or neural etiologies,
radiological assessment of the CPA is performed to assess the presence of anatomical retrocochlear lesions. Traditional protocols
Before the advent of MRI, electronystagmography and Computed Tomography were employed for diagnosis of acoustic neuroma. Auditory brainstem response audiometry and adjunct tests
The auditory brainstem response (ABR) test gives information about the inner ear (cochlea) and nerve pathways for hearing via ongoing electrical activity in the brain measured by electrodes placed on the scalp. Five different waves (I to V) are measured for each ear. Each waveform represents specific anatomical points along the auditory neural pathway. Delays of one side relative to the other suggest a lesion in cranial nerve VIII between the ear and brainstem or in the brainstem itself. The most reliable indicator for acoustic neuromas from the ABR is the interaural latency differences in wave V: the latency in the impaired ear is prolonged. Different studies have indicated the sensitivity of ABR for detection of acoustic neuromas 1cm or larger to be between 90 and 95%. Sensitivity for neuromas smaller than 1cm are 63-77%.
There are conflicting studies on the association between acoustic neuromas and cellular phone use and repeated exposure to loud noise. In 2011, an arm of the World Health Organization released a statement listing cell phone use as a low grade cancer risk. The Acoustic Neuroma Association recommends that cell phone users use a hands-free device. Meningiomas are significantly more common in women than in men; they are most common in middle-aged women. Two predisposing factors associated with meningiomas for which at least some evidence exists are exposure to ionizing radiation (cancer treatment of brain tumors) and hormone replacement therapy. Pathophysiology
Various kinds of tumors, usually primary and benign, are represented in the pathology. Lesions in the area of cerebellopontine angle cause signs and symptoms secondary to compression of nearby cranial nerves, including cranial nerve V (trigeminal), cranial nerve VII (facial), and cranial nerve VIII (vestibulocochlear). The most common cerebellopontine angle (CPA) tumor is a vestibular schwannoma affecting cranial nerve VIII (80%), followed by meningioma (10%).