There are several signs and symptoms of the eye that can indicate the growth of a tumor, which include:

- White or reddening pupil

- Eye enlargement or bulging

- Redness or irritation

- Visual disturbances

- Vision loss or changes

- Drooping eyelid.

Intraocular Schwannoma, also termed uveal schwannoma, is a type of schwannoma found in the eye. These tumors are almost always benign in nature and while malignant forms have been documented in other areas of the body, this has not been reported in the uveal region. Composed of Schwann cells, these masses are generally slow growing and can be found in the peripheral nerve tract, often around the head and neck.

A nerve sheath tumor is a type of tumor of the nervous system (nervous system neoplasm) which is made up primarily of the myelin surrounding nerves.

A peripheral nerve sheath tumor (PNST) is a nerve sheath tumor in the peripheral nervous system. Benign peripheral nerve sheath tumors include schwannomas and neurofibromas.

A malignant peripheral nerve sheath tumor (MPNST) is a cancerous peripheral nerve sheath tumor.

A schwannoma is a usually-benign nerve sheath tumor composed of Schwann cells, which normally produce the insulating myelin sheath covering peripheral nerves.

3 affected domains of neurological function:

- Cerebral hemisphere (15%)

- Cranial Nerves (35%)

- Spinal cord and roots (60%)

Signs reported

- headache

- mental status change

- confusion

- cognitive impairment

- seizures

- hemiparesis

- gait instability

Other symptoms that are less common are dementia, autonomic dysfunction, cranial nerve abnormalities, spinal symptoms such as limb weakness and paresthesia, and bowel and bladder dysfunction. Diplopia is the most common symptom of cranial nerve dysfunction. Trigeminal sensory or motor loss, cochlear dysfunction, and optic neuropathy are also common findings. Spinal signs and symptoms include weakness, dermatomal or segmental sensory loss, and pain in the neck, back, or following radicular patterns.

A nervous system neoplasm is a tumor affecting the nervous system. Types include:

- Nerve sheath tumor

- Brain tumor

- Arachnoid cyst

- Optic nerve glioma

Schwannomas are homogeneous tumors, consisting only of Schwann cells. The tumor cells always stay on the outside of the nerve, but the tumor itself may either push the nerve aside and/or up against a bony structure (thereby possibly causing damage). Schwannomas are relatively slow-growing. For reasons not yet understood, schwannomas are mostly benign and less than 1% become malignant, degenerating into a form of cancer known as neurofibrosarcoma. These masses are generally contained within a capsule, and so surgical removal is often successful.

Schwannomas can be associated with neurofibromatosis type II, which may be due to a loss-of-function mutation in the protein merlin. They are universally S-100 positive, which is a marker for cells of neural crest cell origin.

Schwannomas of the head and neck are a fairly common occurrence and can be found incidentally in 3–4% of patients at autopsy. Most common of these is a vestibular schwannoma, a tumor of the vestibulocochlear nerve that may lead to tinnitus and hearing loss on the affected side. Outside the cranial nerves, schwannomas may present on the flexor surfaces of the limbs. Rare occurrences of these tumors in the penis have been documented in the literature.

Verocay bodies are seen histologically in schwannomas.

Jacod Syndrome is commonly associated with a tumor of the middle cranial fossa (near the apex of the orbit); but it can have several other causes.

The most common finding is oculomotor nerve dysfunction leading to ophthalmoplegia. This is often accompanied by ophthalmic nerve dysfunction, leading to hypoesthesia of the upper face. The optic nerve may eventually be involved, with resulting visual impairment.

Tumors within the nerve canaliculi initially present with unilateral sensorineural hearing loss, unilateral tinnitus, or disequilibrium (vertigo is rare, on account of the slow growth of neuromas). Speech discrimination out of proportion to hearing loss, difficulty talking on the telephone are frequent accompaniments. Tumors extending into the CPA will likely present with disequilibrium or ataxia depending on the amount of extension on the brainstem. With brainstem extension, midfacial and corneal hypesthesia, hydrocephalus, and other cranial neuropathies become more prevalent.

For example, involvement of CN V from a cerebellopontine mass lesion often results in loss of the ipsilateral (same side of the body) corneal reflex (involuntary blink).

Patients with larger tumours can develop Bruns nystagmus ('dancing eyes') due to compression of the flocculi.

Neurofibromatosis (NF1) in early life may cause learning and behavior problems – about 60% of children who have NF1 have a mild form of difficulty in school. In terms of signs the individual might have are the following:

- Six or more light brown dermatological spots ("café au lait spots")

- At least two neurofibromas

- At least two growths on the eye's iris

- Abnormal growth of the spine (scoliosis)

Neurofibromatosis type II (also known as MISME syndrome - multiple inherited schwannomas, meningiomas, and ependymomas) is a genetic condition which may be inherited or may arise spontaneously. The main manifestation of the condition is the development of symmetric, benign brain tumors in the region of the cranial nerve VIII, which is the "auditory-vestibular nerve" that transmits sensory information from the inner ear to the brain. Many people with this condition also experience visual problems. NF II is caused by mutations of the "Merlin" gene, which seems to influence the form and movement of cells. The principal treatments consist of neurosurgical removal of the tumors and surgical treatment of the eye lesions. Historically the underlying disorder has not had any therapy due to the cell function caused by the genetic mutation. However, new drug research and some clinical trials have shown some promise in having beneficial effects. Collaborative research to find better treatments is ongoing, such as the work of the Synodos NF-2 Consortium of scientists.

The clinical spectrum of the condition is broad. In other words, people with NF II may develop a wide range of distinct problems.

1. Acoustic nerve: 90% of the patients show bilateral acoustic schwannomas on magnetic resonance imaging (MRI).

2. Other cranial nerves and meninges: About 50% of patients develop tumours in other cranial nerves or meningiomas.

3. Spinal cord: About 50% of the patients develop spinal lesions. Only 40% of the spinal lesions are symptomatic. The spinal tumours in NF II are separated in two groups. Intramedullary lesions are located within the spinal tissue and usually belong to the so-called spinal astrocytomas or ependymomas. The extramedullary lesions are located within the small space between the surface of the spinal cord and the bony wall of the spinal canal. These tumours belong to the schwannomas and meningiomas.

4. Skin: If children show neurofibromas, a diagnostic procedure should be performed to decide which form of neurofibromatosis causes the alterations.

5. Eyes: Studies on patients with NF II show that more than 90% of the affected persons suffer eye lesions. The most common alteration in NF II is the juvenile subcapsular cataract (opacity of the lens) in young people.

"Presenting symptoms" (initial concern that brings a patient to a doctor) of a lesion of the nervus vestibulocochlearis due to a tumour in the region of the cerebello-pontine angle are the following: hearing loss (98%), tinnitus (70%), dysequilibrium (67%), headache (32%), facial numbness and weakness (29% and 10% respectively).

"Clinical signs" (alterations that are not regarded by the patient and that can be detected by the doctor in a clinical examination) of the lesion in discussion are: abnormal corneal reflex (33%), nystagmus (26%), facial hypesthesia (26%).

Evaluation (study of the patient with technical methods) shows the enlargement of the porus acousticus internus in the CT scan, enhancing tumours in the region of the cerebello-pontine angle in gadolinium-enhanced MRI scans, hearing loss in audiometric studies and perhaps pathological findings in electronystagmography. Some times there are elevated levels of protein in liquor study.

In NF II, acoustic neuromas usually affect young people, whereas in sporadic forms of acoustic neuromas, the appearance of the tumour is limited to the elderly.

There are two forms of the NF II:

- The "Wishart-Phenotype" is characterized by multiple cerebral and spinal lesions in patients younger than 20 years and with rapid progression of the tumours.

- Patients that develop single central tumours with slow progression after age of 20 are thought to have the "Feiling-Gardner-Phenotype".

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.

Symptoms are usually limited to one side of the head, and in most cases the individual affected will experience intense, sharp pain and paralysis of muscles around the eye. Symptoms may subside without medical intervention, yet recur without a noticeable pattern.

In addition, affected individuals may experience paralysis of various facial nerves and drooping of the upper eyelid (ptosis). Other signs include double vision, fever, chronic fatigue, vertigo or arthralgia. Occasionally the patient may present with a feeling of protrusion of one or both eyeballs (exophthalmos).

The most common symptom of the papillary tumor is a headache. Because headaches are so common, most people think nothing of it. This is why brain tumors are so dangerous. There are not a lot of symptoms that go along with them so people tend to wait a long time before seeking medical help. Most of the time people will go see a doctor when their headaches become consistent and start to never go away. This symptom however occurs secondary to hydrocephalus, which is a result from compression of the cerebral aqueduct. The cerebral aqueduct is a narrow channel in the midbrain, which connects the third and fourth ventricles. When a tumor blocks the pathway of the cerebrospinal fluid, this will cause headaches in the patient. Often when hydrocephalus occurs, a shunt is put in place in order to alleviate the pressure. In one case study, an endoscopic third ventriculostomy was performed as a first line procedure to treat the hydrocephalus and also for diagnostic purposes.

In some cases, patients have had progressive diplopia, or double vision. Also, although not in all cases, patients sometimes suffer from nausea and vomiting.

The morning glory disc anomaly (MGDA) is a congenital deformity resulting from failure of the optic nerve to completely form in utero. The term was coined in 1970 by Kindler, noting a resemblance of the malformed optic nerve to the morning glory flower. The condition is usually unilateral.

On fundoscopic examination, there are three principal findings comprising the anomaly:

1. an enlarged, funnel-shaped excavation in optic disc

2. an annulus or ring of pigmentary changes surrounding the optic disc excavation

3. a central glial tuft overlying the optic disc

Neoplastic or malignant meningitis, also called meningitis carcinomatosa and leptomeningeal carcinomatosis, is the development of meningitis due to infiltration of the subarachnoid space by cancerous cells. Malignant cells come from primary cancer such as breast cancer or from a primary brain tumor like medulloblastoma. Neoplastic Meningitis (NM) was first reported in the 1870s with the most common cause being breast cancer, lung cancer, and malignant melanoma.

The most common symptom of IIH is headache, which occurs in almost all (92–94%) cases. It is characteristically worse in the morning, generalized in character and throbbing in nature. It may be associated with nausea and vomiting. The headache can be made worse by any activity that further increases the intracranial pressure, such as coughing and sneezing. The pain may also be experienced in the neck and shoulders. Many have pulsatile tinnitus, a whooshing sensation in one or both ears (64–87%); this sound is synchronous with the pulse. Various other symptoms, such as numbness of the extremities, generalized weakness, loss of smell, and loss of coordination, are reported more rarely; none are specific for IIH. In children, numerous nonspecific signs and symptoms may be present.

The increased pressure leads to compression and traction of the cranial nerves, a group of nerves that arise from the brain stem and supply the face and neck. Most commonly, the abducens nerve (sixth nerve) is involved. This nerve supplies the muscle that pulls the eye outward. Those with sixth nerve palsy therefore experience horizontal double vision which is worse when looking towards the affected side. More rarely, the oculomotor nerve and trochlear nerve (third and fourth nerve palsy, respectively) are affected; both play a role in eye movements. The facial nerve (seventh cranial nerve) is affected occasionally –- the result is total or partial weakness of the muscles of facial expression on one or both sides of the face.

The increased pressure leads to papilledema, which is swelling of the optic disc, the spot where the optic nerve enters the eyeball. This occurs in practically all cases of IIH, but not everyone experiences symptoms from this. Those who do experience symptoms typically report "transient visual obscurations", episodes of difficulty seeing that occur in both eyes but not necessarily at the same time. Long-term untreated papilledema leads to visual loss, initially in the periphery but progressively towards the center of vision.

Physical examination of the nervous system is typically normal apart from the presence of papilledema, which is seen on examination of the eye with a small device called an ophthalmoscope or in more detail with a fundus camera. If there are cranial nerve abnormalities, these may be noticed on eye examination in the form of a squint (third, fourth, or sixth nerve palsy) or as facial nerve palsy. If the papilledema has been longstanding, visual fields may be constricted and visual acuity may be decreased. Visual field testing by automated (Humphrey) perimetry is recommended as other methods of testing may be less accurate. Longstanding papilledema leads to optic atrophy, in which the disc looks pale and visual loss tends to be advanced.

Although the finding itself is rare, MGDA can be associated with midline cranial defects and abnormal carotid circulation, such as carotid stenosis/aplasia or progressive vascular obstruction with collateralization (also known as moyamoya disease). The vascular defects may lead to ischemia, stroke, or seizures and so a finding of MGDA should be further investigated with radiographic imaging.

In most cases, symptoms of NF1 are mild, and individuals live normal and productive lives. In some cases, however, NF1 can be severely debilitating and may cause cosmetic and psychological issues. The course of NF2 varies greatly among individuals. In some cases of NF2, the damage to nearby vital structures, such as other cranial nerves and the brain stem, can be life-threatening. Most individuals with schwannomatosis have significant pain. In some extreme cases the pain will be severe and disabling.

Tolosa–Hunt syndrome (THS) is a rare disorder characterized by severe and unilateral headaches with orbital pain, along with weakness and paralysis (ophthalmoplegia) of certain eye muscles (extraocular palsies).

In 2004, the International Headache Society provided a definition of the diagnostic criteria which included granuloma.

Papillary tumors of the pineal region (PTPR) were first described by A. Jouvet et al. in 2003 and were introduced in the World Health Organization (WHO) classification of Central Nervous System (CNS) in 2007. Papillary Tumors of the Pineal Region are located on the pineal gland which is located in the center of the brain. The pineal gland is located on roof of the diencephalon. It is a cone shaped structure dorsal to the midbrain tectum. The tumor appears to be derived from the specialized ependymal cells of the subcommissural organ. Papillary tumors of the central nervous system and particularly of the pineal region are very rare and so diagnosing them is extremely difficult.

Symptoms of gliomas depend on which part of the central nervous system is affected. A brain glioma can cause headaches, vomiting, seizures, and cranial nerve disorders as a result of increased intracranial pressure. A glioma of the optic nerve can cause visual loss. Spinal cord gliomas can cause pain, weakness, or numbness in the extremities. Gliomas do not metastasize by the bloodstream, but they can spread via the cerebrospinal fluid and cause "drop metastases" to the spinal cord.

A child who has a subacute disorder of the central nervous system that produces cranial nerve abnormalities (especially of cranial nerve VII and the lower bulbar nerves), long-tract signs, unsteady gait secondary to spasticity, and some behavioral changes is most likely to have a pontine glioma.

This produces ipsilateral horizontal gaze palsy and facial nerve palsy and contralateral hemiparesis, hemisensory loss, and internuclear ophthalmoplegia.