Central Nervous System Germ Cell Tumor

Central Nervous System Germ Cell Tumors (CNS GCTs) are rare tumors originating from germ cells that abnormally migrate and become lodged in the central nervous system (CNS). These tumors are most commonly found in children and young adults, typically presenting in the pineal or suprasellar regions of the brain.

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CNS germ cell tumors are broadly categorized into two groups:

1. Germinomas:

1. The most common type of CNS GCT.

1. Highly sensitive to radiation and chemotherapy.

1. Typically have a favorable prognosis.

2. Non-Germinomatous Germ Cell Tumors (NGGCTs):

1. Include teratomas, yolk sac tumors, embryonal carcinomas, and choriocarcinomas.

1. More aggressive than germinomas.

1. Often requires intensive multimodal therapy.

1. May secrete markers such as alpha-fetoprotein (AFP) or beta-human chorionic gonadotropin (β-hCG).

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Common Locations:

- Pineal Region: Germinomas are frequently found here, often causing symptoms due to compression of surrounding structures.

- Suprasellar Region: May affect the pituitary-hypothalamic axis, leading to hormonal imbalances.

- Other Sites: Rarely, these tumors can occur elsewhere in the brain or spine.

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Symptoms:

Symptoms depend on the tumor's location and size, often including:

1. Increased Intracranial Pressure (e.g., headaches, nausea, vomiting, papilledema):

1. Due to hydrocephalus from obstruction of cerebrospinal fluid (CSF) flow.

2. Neurological Symptoms:

1. Double vision, ataxia, or weakness, depending on the affected brain region.

3. Endocrine Dysfunction (especially in suprasellar tumors):

1. Diabetes insipidus.

1. Delayed or precocious puberty.

1. Hypopituitarism.

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see Germ Cell Tumor diagnosis.

### Treatment: 1. Germinomas:

1. Radiation Therapy: Mainstay of treatment, often with curative intent.
2. Chemotherapy: Used in conjunction with radiation to reduce the radiation dose and long-term side effects.

2. Non-Germinomatous Germ Cell Tumors (NGGCTs):

1. Multimodal Approach:
   1. Surgery for resection when feasible.
   2. Chemotherapy (e.g., cisplatin-based regimens).
   3. Radiation therapy tailored to the extent of the disease.

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### Prognosis: 1. Germinomas:

1. 5-year survival rate >90% with appropriate treatment.

2. NGGCTs:

1. Prognosis varies by subtype and extent of disease.
2. Tumors secreting high levels of AFP or β-hCG often have a poorer prognosis.

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### Follow-Up: Patients require long-term monitoring for: 1. Recurrence through imaging and tumor marker levels. 2. Late effects of therapy, including neurocognitive impairment, endocrine dysfunction, and secondary malignancies.

CNS GCTs, though rare, are often treatable with a combination of surgery, radiation, and chemotherapy, particularly when detected early. Multidisciplinary care is essential for optimizing outcomes.