For malignant teratomas, usually, surgery is followed by chemotherapy.

Teratomas that are in surgically inaccessible locations, or are very complex, or are likely to be malignant (due to late discovery and/or treatment) sometimes are treated first with chemotherapy.

The treatment of choice is complete surgical removal ("i.e.," complete resection). Teratomas are normally well-encapsulated and non-invasive of surrounding tissues, hence they are relatively easy to resect from surrounding tissues. Exceptions include teratomas in the brain, and very large, complex teratomas that have pushed into and become interlaced with adjacent muscles and other structures.

Prevention of recurrence does not require "en bloc" resection of surrounding tissues.

Treatment is often largely dependent on the type of cyst. Asymptomatic cysts, termed pseudocysts, normally require active monitoring with periodic scans for future growth. Symptomatic (producing or showing symptoms) cysts may require surgical removal if they are present in areas where brain damage is unavoidable, or if they produce chronic symptoms disruptive to the quality of life of the patient. Some examples of cyst removal procedures include: permanent drainage, fenestration, and endoscopic cyst fenestration.

A neurosurgeon performs a same day surgery to insert an endoscope, which drains the cyst internally.

The treatment for hemangioblastoma is surgical excision of the tumor. Although usually straightforward to carry out, recurrence of the tumor or more tumors at a different site develop in approximately 20% of patients. Gamma Knife Radiosurgery as well as LINAC have also been employed to successfully treat recurrence and control tumor growth of cerebellar hemangioblastomas.

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.

SCTs are very rare in adults, and as a rule these tumors are benign and have extremely low potential for malignancy. This estimation of potential is based on the idea that because the tumor existed for decades prior to diagnosis, without becoming malignant, it has little or no potential to ever become malignant. For this reason, and because coccygectomy in adults has greater risks than in babies, some surgeons prefer not to remove the coccyx of adult survivors of SCT. There are case reports of good outcomes.

Management of most fetal SCTs involves watchful waiting prior to any treatment. An often used decision tree is as follows:

- Perform detailed ultrasound exam including fetal echocardiogram and Doppler flow analysis

- If fetal high output failure, placentomegaly, or hydrops

- If fetus not mature, perform pregnancy termination or fetal intervention

- Else fetus mature, perform emergency Cesarean section

- Else no emergent problems, perform serial non-stress tests and ultrasound biophysical profiles and plan delivery, as follows

- If emergent problems develop, return to top of decision tree

- Else if SCT over 5–10 cm or polyhydramnios, perform early (37 weeks gestation) elective Cesarean section

- Else SCT small and no complications, permit term spontaneous vaginal delivery

Emergent problems include maternal mirror syndrome, polyhydramnios, and preterm labor. Poor management decisions, including interventions that are either premature or delayed, can have dire consequences. A very small retrospective study of 9 babies with SCTs greater than 10 cm diameter reported slightly higher survivorship in babies remaining in utero slightly longer.

In many cases, a fetus with a small SCT (under 5 or 10 cm) may be delivered vaginally. Prior to the advent of prenatal detection and hence scheduled C-section, 90% of babies diagnosed with SCT were born full term.

Most treatments involve some combination of surgery and chemotherapy. Treatment with cisplatin, etoposide, and bleomycin has been described.

Before modern chemotherapy, this type of neoplasm was highly lethal, but the prognosis has significantly improved since.

When endodermal sinus tumors are treated promptly with surgery and chemotherapy, fatal outcomes are exceedingly rare.

Treatment for dermoid cyst is complete surgical removal, preferably in one piece and without any spillage of cyst contents. Marsupialization, a surgical technique often used to treat pilonidal cyst, is inappropriate for dermoid cyst due to the risk of malignancy.

The association of dermoid cysts with pregnancy has been increasingly reported. They usually present the dilemma of weighing the risks of surgery and anesthesia versus the risks of untreated adnexal mass. Most references state that it is more feasible to treat bilateral dermoid cysts of the ovaries discovered during pregnancy if they grow beyond 6 cm in diameter.

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.

Treatment also involves central nervous system penetrating chemotherapy. Options include intrathecal, intraventricular, and systemic chemotherapy. These must penetrate the blood-brain barrier in order to be effective. Sometimes mixing multiple forms of treatment with chemotherapy seems to be the best route. For example, some significant improvement has been shown as a result of cranial radiation treatment preceding a brief course of intrathecal chemotherapy. Although this is an effective treatment to do, penetrating the blood-brain barrier can cause side effects due to the toxicity in the nervous system. These would include dizziness, confusion, and changes in mental status. Another form could be the use of pharmaceuticals, which have all shown positive results for treatment but should always be consulted with a physician to asses risks.

Women with benign germ cell tumors such as mature teratomas (dermoid cysts) are cured by ovarian cystectomy or oophorectomy. In general, all patients with malignant germ cell tumors will have the same staging surgery that is done for epithelial ovarian cancer. If the patient is in her reproductive years, an alternative is unilateral salpingoophorectomy, while the uterus, the ovary, and the fallopian tube on the opposite side can be left behind. This isn't an option when the cancer is in both ovaries. If the patient has finished having children, the surgery involves complete staging including salpingoophorectomy on both sides as well as hysterectomy.

Most patients with germ cell cancer will need to be treated with combination chemotherapy for at least 3 cycles. The chemotherapy regimen most commonly used in germ cell tumors is called PEB (or BEP), and consists of bleomycin, etoposide, a platinum-based antineoplastic (cisplatin).

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.

The 1997 International Germ Cell Consensus Classification is a tool for estimating the risk of relapse after treatment of malignant germ cell tumor.

A small study of ovarian tumors in girls reports a correlation between cystic and benign tumors and, conversely, solid and malignant tumors. Because the cystic extent of a tumor can be estimated by ultrasound, MRI, or CT scan before surgery, this permits selection of the most appropriate surgical plan to minimize risk of spillage of a malignant tumor.

Access to appropriate treatment has a large effect on outcome. A 1993 study of outcomes in Scotland found that for 454 men with non-seminomatous (non-germinomatous) germ cell tumors diagnosed between 1975 and 1989, 5-year survival increased over time and with earlier diagnosis. Adjusting for these and other factors, survival was 60% higher for men treated in a cancer unit that treated the majority of these men, even though the unit treated more men with the worst prognosis.

Choriocarcinoma of the testicles has the worst prognosis of all germ cell cancers

Most fetuses with triploidy do not survive to birth, and those that do usually pass within days. As there is no treatment for Triploidy, palliative care is given if a baby survives to birth. If Triploidy is diagnosed during the pregnancy, termination is often offered as an option due to the additional health risks for the mother (preeclampsia, a life-threatening condition, or choriocarcinoma, a type of cancer). Should a mother decide to carry until term or until a spontaneous miscarriage occurs, doctors will monitor her closely in case either condition develops.

Mosaic triploidy has an improved prognosis, but affected individuals have moderate to severe cognitive disabilities.

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 is a wide range of treatments for central nervous system diseases. These can range from surgery to neural rehabilitation or prescribed medications.

Polyembryoma is a rare, very aggressive form of germ cell tumor usually found in the ovaries. Polyembryoma has features of both yolk sac tumour and undifferentiated teratoma/embryonal carcinoma, with a characteristic finding of embryoid bodies lying in a loose mesenchymal stroma.

It has been found in association with Klinefelter syndrome.

MEM comprises a heterogeneous group of neoplasms believed to originate from the neural crest. First hints to this type of tumor were probably from Shuangshoti and Nestky (1971) and from Holimon and Rosenblum (1971) (2-3). Additional contributions were provided thereafter by Naka et al. (1975), Karcioglu et al. (1977), Cozzutto et al. (1982) and Kawamoto et al. (1987).

Kosem et al. collected 44 cases of MEM in a 2004 review and examined management data finding out that resection with pre- or post-surgery chemotherapy yielded the best results with one death only in 13. In the five cases reported by Mouton et al. an aggressive chemotherapy and adequate surgical excision granted a disease-free interval for 7 to 50 months. The attainability of radical surgical

ablation seems the most important prognostic factor (10).

There is no known treatment to reverse nerve damage due to myelomalacia. In some cases, surgery may slow or stop further damage. As motor function degenerates, muscle spasticity and atrophy may occur. Steroids may be prescribed to reduce swelling of the spinal cord, pain, and spasticity.

Research is underway to consider the potential of stem cells for treatment of neurodegenerative diseases. There are, however, no approved stem cell therapies for myelomalacia.

Since each case is different, the following are possible treatments that patients might receive in the management of myelitis.

- Intravenous steroids

High-dose intravenous methyl-prednisolone for 3–5 days is considered as a standard of care for patients suspected to have acute myelitis, unless there are compelling reasons otherwise. The decision to offer continued steroids or add a new treatment is often based on the clinical course and MRI appearance at the end of 5 days of steroids.

- Plasma exchange (PLEX)

Patients with moderate to aggressive forms of disease who don’t show much improvement after being treated with intravenous and oral steroids will be treated with PLEX. Retrospective studies of patients with TM treated with IV steroids followed by PLEX showed a positive outcome. It also has been shown to be effective with other autoimmune or inflammatory central nervous system disorders. Particular benefit has been shown with patients who are in the acute or subacute stage of the myelitis showing active inflammation on MRI. However, because of the risks implied by the lumbar puncture procedure, this intervention is determined by the treating physician on a case-by-case basis.

- Immunosuppressants/Immunomodulatory agents

Myelitis with no definite cause seldom recurs, but for others, myelitis may be a manifestation of other diseases that are mentioned above. In these cases, ongoing treatment with medications that modulate or suppress the immune system may be necessary. Sometimes there is no specific treatment. Either way, aggressive rehabilitation and long-term symptom management are an integral part of the healthcare plan.

An immature teratoma is a rare type of malignant (cancerous) germ cell tumor (type of tumor that begins in the cells that give rise to sperm or eggs).

Like a mature teratoma, it contains several different types of tissue such as hair, muscle, and bone. Unlike a mature teratoma, it contains primitive neuroepithelium.

Due to the lack of knowledge around the underlying mechanism of MAP, an effective treatment method has not been developed. Treatment for this condition is symptomatic. However, several treatment methods have been tested and are still being developed as more information regarding the condition is found. Fibrinolytic and immunosuppresive therapeutic regimens were tested and found to be mostly unsuccessful as treatment methods.

After treating conditions comorbid with Degos disease, physicians have recently found improvement in symptoms with the use of eculizumab and treprostinil. Discovered by dermatopathologist, Cynthia Magro, response to eculizumab is often immediate and dramatic, but has been of limited duration and is expensive, needing to be infused every 14 days. Treprostinil use has been reported to result in clearing of gastrointestinal and central nervous system findings as well as clearing of cutaneous lesions, but reports are limited. Treprostinil may be more effective than other vasodilators because it may also increase the population of circulating endothelial cells, allowing angiogenesis.

Immunosuppressive therapies, encompassing corticosteroids, azathioprine, methotrexate and more recently, rituximab, are the mainstay of therapy. Other treatments include PE, IVIG, and thymectomy. Patients reportedly exhibited a heterogenous response to immunomodulation.

Antiepileptics can be used for symptomatic relief of peripheral nerve hyperexcitability. Indeed, some patients have exhibited a spontaneous remission of symptoms.