Choroid plexus tumors have an annual incidence of about 0.3 per 1 million cases.

It is seen mainly in children under the age of 5, representing 5% of all pediatric tumors and 20% of tumors in children less than 1 year old. There has been no link between sex and occurrence.

Although choroid plexus carcinomas are significantly more aggressive and have half the survival rate as choroid plexus papillomas, they are outnumbered in incidence by 5:1 in all age groups. Clinical studies have shown that patients who receive a total resection of a tumor have a 86% survival rate, while patients who only receive a partial resection have a 26% 5-year survival rate. Many incomplete resections result in recurrence within 2 years of primary surgery.

The cause of choroid plexus carcinomas are relatively unknown, although hereditary factors are suspected. The sometimes occur in conjunction with other hereditary cancers, including Li–Fraumeni syndrome and malignant rhabdoid tumors. A mutation in the tumor suppressor gene TP53 is usually characterized in this disease.

Adult survivors of childhood cancer have some physical, psychological, and social difficulties.

Premature heart disease is a major long-term complication in adult survivors of childhood cancer. Adult survivors are eight times more likely to die of heart disease than other people, and more than half of children treated for cancer develop some type of cardiac abnormality, although this may be asymptomatic or too mild to qualify for a clinical diagnosis of heart disease.

Dysgerminoma is the most common type of malignant germ cell ovarian cancer. Dysgerminoma usually occurs in adolescence and early adult life; about 5% occur in pre-pubertal children. Dysgerminoma is extremely rare after age 50. Dysgerminoma occurs in both ovaries in 10% of patients and, in a further 10%, there is microscopic tumor in the other ovary.

Seminoma is the second most common testicular cancer; the most common is mixed, which may contain seminoma.

Abnormal gonads (due to gonadal dysgenesis and androgen insensitivity syndrome) have a high risk of developing a dysgerminoma. Most dysgerminomas are associated with elevated serum lactic dehydrogenase (LDH), which is sometimes used as a tumor marker.

Metastases are most often present in the lymph nodes.

A germinoma is a type of germ cell tumor, which is not differentiated upon examination. It may be benign or malignant.

Hemangioblastomas can cause polycythemia due to ectopic production of erythropoietin as a paraneoplastic syndrome.

Children with cancer are at risk for developing various cognitive or learning problems. These difficulties may be related to brain injury stemming from the cancer itself, such as a brain tumor or central nervous system metastasis or from side effects of cancer treatments such as chemotherapy and radiation therapy. Studies have shown that chemo and radiation therapies may damage brain white matter and disrupt brain activity.

Dysgerminomas, like other seminomatous germ cell tumors, are very sensitive to both chemotherapy and radiotherapy. For this reason, with treatment patients' chances of long-term survival, even cure, is excellent.

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.

Ependymomas make up about 5% of adult intracranial gliomas and up to 10% of childhood tumors of the central nervous system (CNS). Their occurrence seems to peak at age 5 years and then again at age 35. They develop from cells that line both the hollow cavities of the brain and the canal containing the spinal cord, but they usually arise from the floor of the fourth ventricle, situated in the lower back portion of the brain, where they may produce headache, nausea and vomiting by obstructing the flow of cerebrospinal fluid. This obstruction may also cause hydrocephalus. They may also arise in the spinal cord, conus medullaris and supratentorial locations. Other symptoms can include (but are not limited to): loss of appetite, difficulty sleeping, temporary inability to distinguish colors, uncontrollable twitching, seeing vertical or horizontal lines when in bright light, and temporary memory loss. It should be remembered that these symptoms also are prevalent in many other illnesses not associated with ependymoma.

About 10% of ependymomas are benign myxopapillary ependymoma (MPE). MPE is a localized and slow-growing low-grade tumor, which originates almost exclusively from the lumbosacral nervous tissue of young patients. On the other hand, it is the most common tumor of the lumbosacral canal comprising about 90% of all tumoral lesions in this region.

Although some ependymomas are of a more anaplastic and malignant type, most of them are not anaplastic. Well-differentiated ependymomas are usually treated with surgery. For other ependymomas, total surgical removal is the preferred treatment in addition to radiation therapy. The malignant (anaplastic) varieties of this tumor, malignant ependymoma and the ependymoblastoma, are treated similarly to medulloblastoma but the prognosis is much less favorable. Malignant ependymomas may be treated with a combination of radiation therapy and chemotherapy. Ependymoblastomas, which occur in infants and children younger than 5 years of age, may spread through the cerebrospinal fluid and usually require radiation therapy. The subependymoma, a variant of the ependymoma, is apt to arise in the fourth ventricle but may occur in the septum pellucidum and the cervical spinal cord. It usually affects people over 40 years of age and more often affects men than women.

Extraspinal ependymoma (EEP), also known as extradural ependymoma, may be an unusual form of teratoma or may be confused with a sacrococcygeal teratoma.

A dysgerminoma is a type of germ cell tumor; it usually is malignant and usually occurs in the ovary.

A tumor of the identical histology but not occurring in the ovary may be described by an alternate name: seminoma in the testis or germinoma in the central nervous system or other parts of the body.

Dysgerminoma accounts for less than 1% of ovarian tumors overall. Dysgerminoma usually occurs in adolescence and early adult life; about 5% occur in pre-pubertal children. Dysgerminoma is extremely rare after age 50. Dysgerminoma occurs in both ovaries in 10% of patients and, in a further 10%, there is microscopic tumor in the other ovary.

Abnormal gonads (due to gonadal dysgenesis and androgen insensitivity syndrome) have a high risk of developing a dysgerminoma. Most dysgerminomas are associated with elevated serum lactic dehydrogenase (LDH), which is sometimes used as a tumor marker.

Ependymoma is a tumor that arises from the ependyma, a tissue of the central nervous system. Usually, in pediatric cases the location is intracranial, while in adults it is spinal. The common location of intracranial ependymoma is the fourth ventricle. Rarely, ependymoma can occur in the pelvic cavity.

Syringomyelia can be caused by an ependymoma.

Ependymomas are also seen with neurofibromatosis type II.

Spermatocytic seminomas are not considered a subtype of seminoma and unlike other germ cell tumours do not arise from intratubular germ cell neoplasia.

Seminoma (also known as "pure seminoma" or "classical seminoma") is a germ cell tumor of the testicle or, more rarely, the mediastinum or other extra-gonadal locations. It is a malignant neoplasm and is one of the most treatable and curable cancers, with a survival rate above 95% if discovered in early stages.

Testicular seminoma originates in the germinal epithelium of the seminiferous tubules. About half of germ cell tumors of the testicles are seminomas. Treatment usually requires removal of one testicle. However, fertility usually isn't affected. All other sexual functions will remain intact.

A neuroectodermal tumor is a tumor of the central or peripheral nervous system.

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.

There are no known risk factors that have been identified specific to the disease. The tumor appears to arise from the primitive cells of childhood, and is considered a childhood cancer.

Research has indicated that there is a chimeric relationship between desmoplastic small-round-cell tumor (DSRCT) and Wilms' tumor and Ewing's sarcoma. Together with neuroblastoma and non-Hodgkin's lymphoma, they form the small cell tumors.

DSRCT is associated with a unique chromosomal translocation t(11;22)(p13:q12) resulting in an EWS/WT1 transcript that is diagnostic of this tumor. This transcript codes for a protein that acts as a transcriptional activator that fails to suppress tumor growth.

The EWS/WT1 translocation product targets ENT4. ENT4 is also known as PMAT.

The prognosis for DSRCT remains poor. Prognosis depends upon the stage of the cancer. Because the disease can be misdiagnosed or remain undetected, tumors frequently grow large within the abdomen and metastasize or seed to other parts of the body.

There is no known organ or area of origin. DSRCT can metastasize through lymph nodes or the blood stream. Sites of metastasis include the spleen, diaphragm, liver, large and small intestine, lungs, central nervous system, bones, uterus, bladder, genitals, abdominal cavity, and the brain.

A multi-modality approach of high-dose chemotherapy, aggressive surgical resection, radiation, and stem cell rescue improves survival for some patients. Reports have indicated that patients will initially respond to first line chemotherapy and treatment but that relapse is common.

Some patients in remission or with inoperable tumor seem to benefit from long term low dose chemotherapy, turning DSRCT into a chronic disease.

Once a patient with neurocutaneous melanosis becomes symptomatic, little can be done to improve prognosis as there is no effective treatment for the disorder. Most therapies are designed to treat the symptoms associated with the disorder, mainly those related to hydrocephalus. A ventriculoperitoneal shunt to relieve intracranial pressure is the preferred method.

Chemotherapy and radiotherapy have been shown to be ineffective in cases of neurocutaneous melanosis where malignancy is present. Additionally, due to the total infiltration of the central nervous system by these lesions, surgical resection is not a viable treatment option.

It has been demonstrated that early embryonic, post-zygotic somatic mutations in the NRAS gene are implicated in the pathogenesis of NCM. Recently, experimental treatment with MEK162, a MEK inhibitor, has been tried in a patient with NCM and progressive symptomatic leptomeningeal melanocytosis. Pathological studies with immunohistochemical and Western Blot analyses using Ki67 and pERK antibodies showed a potential effect of MEK inhibiting therapy. Further studies are needed to determine whether MEK inhibitors can effectively target NRAS-mutated symptomatic NCM.

Cancer can arise in the form of Malignant peripheral nerve sheath tumor resulting from malignant degeneration of a plexiform neurofibroma.

- Frequency. A plexiform neurofibroma has a lifetime risk of 8–12% of transformation into a malignant tumor.

- Diagnosis. MRI.

- Treatment. Surgery (primary) +/- radiation therapy.

- Mortality. Malignant nerve sheath tumor was the main cause of death (60%) in a study of 1895 patients with NF-1 from France in the time period 1980–2006 indicated excess mortality in NF-1 patients compared to the general population. The cause of death was available for 58 (86.6%) patients. The study found excess mortality occurred among patients aged 10 to 40 years. Significant excess mortality was found in both males and females.

Children with NF-1 can experience social problems, attention problems, social anxiety, depression, withdrawal, thought problems, somatic complaints, learning disabilities and aggressive behavior. Treatments include psychotherapy, antidepressants and cognitive behavioral therapy.

Lastly, radiation is normally used as a rescue type treatment and is not recommended as a first line treatment. The doctor would perform localized radiation therapy at a dose of 30 to 40 Gy on the lesions. This is to limit the amount of radiation and prevent further damage to the nervous system, which could happen due to the toxicity of radiation therapy.

Autologous stem-cell transplants are shown to be an effective treatment. However, this should be only considered for certain people due to toxicity concerns. It is possible that the transplant may cause problems like septic shock.

Research shows that children with cancer are at risk for developing various cognitive or learning problems. These difficulties may be related to brain injury stemming from the cancer itself, such as a brain tumor or central nervous system metastasis or from side effects of cancer treatments such as chemotherapy and radiation therapy. Studies have shown that chemo and radiation therapies may damage brain white matter and disrupt brain activity.

Cognitive problems that have been associated with cancer and its treatments in children include deficits in attention, working memory, processing speed, mental flexibility, persistence, verbal fluency, memory, motor skills, academic achievement and social function. These deficits have been shown to occur irrespective of age, socioeconomic status, months since onset or cessation of treatment, anxiety, fatigue and dosage schedule.

A pinealoma is a tumor of the pineal gland, a part of the brain that produces melatonin. If a pinealoma destroys the cells of the pineal gland in a child, it can cause precocious puberty.