This brain tumour develops from Schwann cells, which are linked to the nervous system, both outside the brain and in the spinal cord. This tumour, Vestibular Schwannoma (also known as Acoustic Neurinoma), is composed of cells that act as "electrical insulation" for nerve cells. It originates in the statoacoustic nerve (part of the inner ear to the brain), formed by the auditory (hearing) and vestibular (balance) nerves.

The main symptoms are related to hearing loss and/or ringing or buzzing noises in the ear (tinnitus). If not treated in time, dizziness, imbalance or headaches may occur.

This slow-growing tumour forms from the pituitary gland, also known as a pituitary adenoma. This gland, located at the base of the skull, produces many hormones responsible for controlling various bodily functions. Related to this "master" gland are adenomas, the most common disease affecting the pituitary gland, which constitute 10-15% of intracranial tumours.
Among the most common symptoms are tiredness, drowsiness, nausea and vomiting. But also nasal discharge of clear fluid, headache or problems with the sense of smell.

This tumour arises from the layers of the meninges, which is the protective membrane around the brain and spinal cord. Due to its location it is not considered a tumour, but is included in this category as it can compress the brain and/or nerves. It is the most common benign type, accounting for more than 30% of cases, and is thought to be related to genetic alterations. It is categorised into grades: (I) the tumour grows slowly; (II) it has an intermediate behaviour, so it can reappear once it is removed; and (III) it is considered aggressive, with very rapid growth.

In this case, the symptoms are related to several senses, not only the ear. Depending on where in the brain the tumour is located, signs can range from blurred vision to loss of smell; seizures, slurred speech or weakness in the limbs are also possible.