The primary diagnosis is made with a computed tomography scan (CT scan). On a scan, hemangioblastoma shows as a well-defined, low attenuation region in the posterior fossa with an enhancing nodule on the wall. Sometimes multiple lesions are present.

Imaging studies such as Computerized Tomography (CT) and Magnetic Resonance Imaging (MRI) can aid diagnosis. Medulloepithelioma appears isodense or hypodense with variable heterogeneity and calcification on non-contrast CT scan, and enhances with contrast. This radiographical finding is consistent with a primitive neuroectodermal tumour, especially in children. Blood studies and imaging studies of the abdomen may be used to detect metastases.

Needle aspiration biopsy can be used to aid diagnosis. Definitive diagnosis requires histopathological examination of surgically excised tumour tissues.

Histologically, medulloepithelioma resemble a primitive neural tube and with neuronal, glial and mesenchymal elements. Flexner-Wintersteiner rosettes may also be observed.

Immunohistochemically, neural tube-like structures are vimentin positive in the majority of medulloepitheliomas. Poorly differentiated medulloepitheliomas are vimentin negative.

An X-ray computed tomography (CT) or magnetic resonance imaging (MRI) scan is necessary to characterize the extent of these tumors (size, location, consistency). CT will usually show distortion of third and lateral ventricles with displacement of anterior and middle cerebral arteries. Histologic analysis is necessary for grading diagnosis.

In the first stage of diagnosis the doctor will take a history of symptoms and perform a basic neurological exam, including an eye exam and tests of vision, balance, coordination and mental status. The doctor will then require a computerized tomography (CT) scan and magnetic resonance imaging (MRI) of the patient's brain. During a CT scan, x rays of the patient's brain are taken from many different directions. These are then combined by a computer, producing a cross-sectional image of the brain. For an MRI, the patient relaxes in a tunnel-like instrument while the brain is subjected to changes of magnetic field. An image is produced based on the behavior of the brain's water molecules in response to the magnetic fields. A special dye may be injected into a vein before these scans to provide contrast and make tumors easier to identify.

If a tumor is found, it will be necessary for a neurosurgeon to perform a biopsy on it. This simply involves the removal of a small amount of tumor tissue, which is then sent to a neuropathologist for examination and grading. The biopsy may take place before surgical removal of the tumor or the sample may be taken during surgery. Grading of the tumor sample is a method of classification that helps the doctor to determine the severity of the astrocytoma and to decide on the best treatment options. The neuropathologist grades the tumor by looking for atypical cells, the growth of new blood vessels, and for indicators of cell division called mitotic figures.

Usually—depending on the interview of the patient and after a clinical exam which includes a neurological exam, and an ophthalmological exam—a CT scan and or MRI scan will be performed. A special dye may be injected into a vein before these scans to provide contrast and make tumors easier to identify. The neoplasm will be clearly visible.

If a tumor is found, it will be necessary for a neurosurgeon to perform a biopsy of it. This simply involves the removal of a small amount of tumorous tissue, which is then sent to a (neuro)pathologist for examination and staging. The biopsy may take place before surgical removal of the tumor or the sample may be taken during surgery.

There are no precise guidelines because the exact cause of astrocytoma is not known.

Regardless of location, all rhabdoid tumours are highly aggressive, have a poor prognosis, and tend to occur in children less than two years of age.

Because of the rarity of these tumors, there is still a lot of unknown information. There are many case studies that have been reported on patients who have been diagnosed with this specific type of tumor. Most of the above information comes from the findings resulting from case studies.

Since Papillary Tumors of the Pineal Region were first described in 2003, there have been seventy cases published in the English literature. Since there is such a small number of cases that have been reported, the treatment guidelines have not been established. A larger number of cases that contain a longer clinical follow-up are needed to optimize the management of patients with this rare disease.

Even though there is a general consensus on the morphology and the immunohistochemical characteristics that is required for the diagnosis, the histological grading criteria have yet to be fully defined and its biological behavior appears to be variable. This specific type of tumor appears to have a high potential for local recurrence with a high tumor bed recurrence rate during the five years after the initial surgery. This suggests the need for a tumor bed boost radiotherapy after surgical resection.

As stated above, the specific treatment guidelines have not yet been established, however, gross total resection of the tumor has been the only clinical factor associated overall and progression-free survival. The value of radiotherapy as well as chemotherapy on disease progression will need to be investigated in future trials. With this information, it will provide important insight into long-term management and may further our understanding of the histologic features of this tumor.

The outcome for hemangioblastoma is very good, if surgical extraction of the tumor can be achieved; excision is possible in most cases and permanent neurologic deficit is uncommon and can be avoided altogether if the tumor is diagnosed and treated early. Persons with VHL syndrome have a bleaker prognosis than those who have sporadic tumors since those with VHL syndrome usually have more than one lesion.

Medical imaging plays a central role in the diagnosis of brain tumors. Early imaging methods – invasive and sometimes dangerous – such as pneumoencephalography and cerebral angiography have been abandoned in favor of non-invasive, high-resolution techniques, especially magnetic resonance imaging (MRI) and computed tomography (CT) scans. Neoplasms will often show as differently colored masses (also referred to as processes) in CT or MRI results.

- Benign brain tumors often show up as hypodense (darker than brain tissue) mass lesions on CT scans. On MRI, they appear either hypodense or isointense (same intensity as brain tissue) on T1-weighted scans, or hyperintense (brighter than brain tissue) on T2-weighted MRI, although the appearance is variable.

- Contrast agent uptake, sometimes in characteristic patterns, can be demonstrated on either CT or MRI scans in most malignant primary and metastatic brain tumors.

- Pressure areas where the brain tissue has been compressed by a tumor also appear hyperintense on T2-weighted scans and might indicate the presence a diffuse neoplasm due to an unclear outline. Swelling around the tumor known as "peritumoral edema" can also show a similar result.

This is because these tumors disrupt the normal functioning of the BBB and lead to an increase in its permeability. However, it is not possible to diagnose high- versus low-grade gliomas based on enhancement pattern alone.

The definitive diagnosis of brain tumor can only be confirmed by histological examination of tumor tissue samples obtained either by means of brain biopsy or open surgery. The histological examination is essential for determining the appropriate treatment and the correct prognosis. This examination, performed by a pathologist, typically has three stages: interoperative examination of fresh tissue, preliminary microscopic examination of prepared tissues, and follow-up examination of prepared tissues after immunohistochemical staining or genetic analysis.

The clinical and pathology differential are different. From a pathology perspective, an endolymphatic sac tumor needs to be separated from metastatic renal cell carcinoma, metastatic thyroid papillary carcinoma, middle ear adenoma, paraganglioma, choroid plexus papilloma, middle ear adenocarcinoma, and ceruminous adenoma.

Radiologically

- Odontogenic Myxoma

- Ameloblastoma

- Central Giant Cell Granuloma

- Adenomatoid odontogenic tumor

Histologically

- Orthokeratocyst

- Radicular cyst (particularly if the OKC is very inflamed)

- Unicystic ameloblastoma

The definitive diagnosis is by histologic analysis, i.e. and examination under the microscope.

Under the microscope, OKCs vaguely resemble keratinized squamous epithelium; however, they lack rete ridges and often have an artifactual separation from their basement membrane.

On a CT scan, The radiodensity of a keratocystic odontogenic tumour is about 30 Hounsfield units, which is about the same as ameloblastomas. Yet, ameloblastomas show more bone expansion and seldom show high density areas.

The histologic diagnosis of malignant rhabdoid tumour depends on identification of characteristic rhabdoid cells—large cells with eccentrically located nuclei and abundant, eosinophilic cytoplasm. However, the histology can be heterogeneous and the diagnosis of MRT can often be difficult. Misclassifications can occur.

In MRTs, the INI1 gene (SMARCB1)on chromosome 22q functions as a classic tumour suppressor gene. Inactivation of INI1 can occur via deletion, mutation, or acquired UPD.

In a recent study, SNP array karyotyping identified deletions or LOH of 22q in 49/51 rhabdoid tumours. Of these, 14 were copy neutral LOH (or acquired UPD), which is detectable by SNP array karyotyping, but not by FISH, cytogenetics, or arrayCGH. MLPA detected a single exon homozygous deletion in one sample that was below the resolution of the SNP array. SNP array karyotyping can be used to distinguish, for example, a medulloblastoma with an isochromosome 17q from a primary rhabdoid tumour with loss of 22q11.2. When indicated, molecular analysis of INI1 using MLPA and direct sequencing may then be employed. Once the tumour-associated changes are found, an analysis of germline DNA from the patient and the parents can be done to rule out an inherited or de novo germline mutation or deletion of INI1, so that appropriate recurrence risk assessments can be made.

Microscopically, an astrocytoma is a mass that looks well-circumscribed and has a large cyst. The neoplasm may also be solid.

Under the microscope, the tumor is seen to be composed of bipolar cells with long "hairlike" GFAP-positive processes, giving the designation "pilocytic" (that is, made up of cells that look like fibers when viewed under a microscope). Some pilocytic astrocytomas may be more fibrillary and dense in composition. There is often presence of Rosenthal fibers, eosinophilic granular bodies and microcysts. Myxoid foci and oligodendroglioma-like cells may also be present, though non-specific. Long-standing lesions may show hemosiderin-laden macrophages and calcifications.

If a patient displays congenital melanocytic nevi or giant congenital melanocytic nevi, the criteria for diagnosis of neurocutaneous melanosis is as follows:

- Melanocytic deposits exist within the central nervous system that are either malignant or benign

- The cutaneous lesions, giant or otherwise, are not malignant

This criteria is typically validated through biopsy of the cutaneous lesions and imaging of the central nervous system. It is important to establish that the cutaneous lesions are benign. If not, then the melanocytic deposits in the central nervous system may be the result of metastasis of cutaneous melanoma and not neurocutaneous melanosis.

Imaging has been shown to be the only reliable detection method for the presence of neurocutaneous melanosis that can be performed in living patients. Currently, the preferred imaging modality for diagnosis of neurocutaneous melanosis is Magnetic Resonance Imaging, although ultrasound is another viable option. The signal due melanin deposits in the leptomeninges typical of neurocutaneous melanosis can be easily detected in MRI scans of patients under four months old. In patients above this age, there is some suggestion that normal brain myelination may partially obscure these signals.

As most patients with neurocutaneous melanosis are asymptomatic, those who are diagnosed through MR imaging are not guarantied to develop symptoms. Those diagnosed who did not develop symptoms ranged from 10% to 68%. This wide range is most likely due to the large number of asymptomatic, undiagnosed patients with neurocutaneous melanosis.

Treatment options include surgery, radiotherapy, radiosurgery, and chemotherapy.

The infiltrating growth of microscopic tentacles in fibrillary astrocytomas makes complete surgical removal difficult or impossible without injuring brain tissue needed for normal neurological function. However, surgery can still reduce or control tumor size. Possible side effects of surgical intervention include brain swelling, which can be treated with steroids, and epileptic seizures. Complete surgical excision of low grade tumors is associated with a good prognosis. However, the tumor may recur if the resection is incomplete, in which case further surgery or the use of other therapies may be required.

Standard radiotherapy for fibrillary astrocytoma requires from ten to thirty sessions, depending on the sub-type of the tumor, and may sometimes be performed after surgical resection to improve outcomes and survival rates. Side effects include the possibility of local inflammation, leading to headaches, which can be treated with oral medication. Radiosurgery uses computer modelling to focus minimal radiation doses at the exact location of the tumor, while minimizing the dose to the surrounding healthy brain tissue. Radiosurgery may be a complementary treatment after regular surgery, or it may represent the primary treatment technique.

Although chemotherapy for fibrillary astrocytoma improve overall survival, it is effective only in about 20% of cases. Researchers are currently investigating a number of promising new treatment techniques including gene therapy, immunotherapy, and novel chemotherapies.

Wide excision is the treatment of choice, although attempting to preserve hearing. Based on the anatomic site, it is difficult to completely remove, and so while there is a good prognosis, recurrences or persistence may be seen. There is no metastatic potential. Patients who succumb to the disease, usually do so because of other tumors within the von Hippel-Lindau complex rather than from this tumor.

The main treatment modalities are surgery, embolization and radiotherapy.

The majority of patients with neurocutaneous melanosis are asymptomatic and therefore have a good prognosis with few complications. Most are not diagnosed, so definitive data in not available. For symptomatic patients, the prognosis is far worse. In patients without the presence of melanoma, more than 50% die within 3 years of displaying symptoms. While those with malignancy have a mortality rate of 77% with most patients displaying symptoms before the age of 2.

The presence of a Dandy-Walker malformation along with neurocutaneous melanosis, as occurs in 10% of symptomatic patients, further deteriorates prognosis. The median survival time for these patients is 6.5 months after becoming symptomatic.

Total resection of the tumour, followed by radiation therapy is the standard treatment modality. Medulloepithelioma of the ciliary body may necessitate enucleation of the eye. Radiation therapy alone may prolong survival. Aggressive chemotherapy with autologous bone marrow transplant is used for metastatic medulloepitheliomas.

Papillary tumors of pineal region are extremely rare, constituting 0.4-1% of all central nervous system tumors. These tumors most commonly occur in adults with the mean age being 31.5. There have been cases reported for people between the ages 5 to 66 years. There is a slight predominance of females who have these tumors.

Anaplastic astrocytoma, Astrocytoma, Central neurocytoma, Choroid plexus carcinoma, Choroid plexus papilloma, Choroid plexus tumor, Dysembryoplastic neuroepithelial tumour, Ependymal tumor, Fibrillary astrocytoma, Giant-cell glioblastoma, Glioblastoma multiforme, Gliomatosis cerebri, Gliosarcoma, Hemangiopericytoma, Medulloblastoma, Medulloepithelioma, Meningeal carcinomatosis, Neuroblastoma, Neurocytoma, Oligoastrocytoma, Oligodendroglioma, Optic nerve sheath meningioma, Pediatric ependymoma, Pilocytic astrocytoma, Pinealoblastoma, Pineocytoma, Pleomorphic anaplastic neuroblastoma, Pleomorphic xanthoastrocytoma, Primary central nervous system lymphoma, Sphenoid wing meningioma, Subependymal giant cell astrocytoma, Subependymoma, Trilateral retinoblastoma.

MASC is currently treated as a low-grade (i.e. Grade 1) carcinoma with an overall favorable prognosis. These cases are treated by complete surgical excision. However, the tumor does have the potential to recur locally and/or spread beyond surgically dissectible margins as well as metastasize to regional lymph nodes and distant tissues, particularly in tumors with histological features indicating a high cell growth rate potential. One study found lymph node metastasis in 5 of 34 MASC patients at initial surgery for the disease; these cases, when evidencing no further spread of disease, may be treated with radiation therapy. The treatment of cases with disease spreading beyond regional lymph nodes has been variable, ranging from simple excision to radical resections accompanied by adjuvant radiotherapy and/or chemotherapy, depending on the location of disease. Mean disease-free survival for MASC patients has been reported to be 92 months in one study.

The tyrosine kinase activity of NTRK3 as well as the ETV6-NTRK3 protein is inhibited by certain tyrosine kinase inhibitory drugs such as Entrectinib and LOXO-101; this offers a potential medical intervention method using these drugs to treat aggressive MASC disease. Indeed, one patient with extensive head and neck MASC disease obtained an 89% fall in tumor size when treated with entrectinib. This suppression lasted only 7 months due to the tumor's acquirement of a mutation in the "ETV6-NTRK3" gene. The newly mutated gene encoded an entrectinib-reisistant "ETV6-NTRK3" protein. Treatment of aggressive forms of MASC with NTRK3-inhibiting tyrosine kinase inhibiting drugs, perhaps with switching to another type of tyrosine kinase inhibitor drug if the tumor acquires resistance to the initial drug, is under study.STARTRK-2

In 2015 the first consensus guidelines for the diagnosis and treatment of chordoma were published in the Lancet Oncology.

In one study, the 10-year tumor free survival rate for sacral chordoma was 46%. Chondroid chordomas appear to have a more indolent clinical course.

In most cases, complete surgical resection followed by radiation therapy offers the best chance of long-term control. Incomplete resection of the primary tumor makes controlling the disease more difficult and increases the odds of recurrence. The decision whether complete or incomplete surgery should be performed primarily depends on the anatomical location of the tumor and its proximity to vital parts of the central nervous system.

Chordomas are relatively radioresistant, requiring high doses of radiation to be controlled. The proximity of chordomas to vital neurological structures such as the brain stem and nerves limits the dose of radiation that can safely be delivered. Therefore, highly focused radiation such as proton therapy and carbon ion therapy are more effective than conventional x-ray radiation.

There are no drugs currently approved to treat chordoma, however a clinical trial conducted in Italy using the PDGFR inhibitor Imatinib demonstrated a modest response in some chordoma patients. The same group in Italy found that the combination of imatinib and sirolimus caused a response in several patients whose tumors progressed on imatinib alone.

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

- Nerve sheath tumor

- Brain tumor

- Arachnoid cyst

- Optic nerve glioma