Intraventricular tumors include benign and malignant tumors that can be treated with unique, minimally invasive surgical approaches.
These tumors include gliomas, metastatic tumors, central neurocytomas, subependymal giant cell astrocytomas (SEGA), meningiomas, ependymomas, subependymomas, germinomas and germ cell tumors, choroid plexus papillomas and carcinomas and medulloblastomas (PNET).
The surgical approach is dependent on the tumor type, size and location specific to the ventricle.
Keyhole Brain Tumor
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The ventricles of the brain are fluid-filled structures that produce the cerebrospinal fluid that bathes the brain and spinal cord. The fluid is produced by the choroid plexus and has no “off switch.” Hence, tumors can block flow regionally, resulting in build-up of fluid and pressure.
There are four ventricles, with the lateral ventricles draining into the third ventricle through the Foramen of Munro. The fluid then flows through the cerebral aqueduct (of Sylvius) into the fourth ventricle where it exits the inside of the brain to circulate around the brain and spinal cord before being absorbed back into the blood stream.
Symptoms of these tumors/cysts can vary depending on their type and location amongst the ventricular system. Typical symptoms include headaches, vision loss or double vision, memory loss, imbalance, swallowing difficulties or hoarse voice.
These symptoms can take years to develop, but can worsen suddenly, progressing to altered mental status and coma if left untreated.
As the treatment(s) of these lesions vary greatly on the diagnosis, numerous tests may be necessary prior to surgery. Typical imaging studies include magnetic resonance imaging (MRI) or computer tomography (CT) scans of the brain.
Fiber tractography MRI (DTI) is helpful to assess key neural fibers as well as surgical approach. The cerebrospinal fluid (CSF) may need to be analyzed via a lumbar puncture (spinal tap) if deemed safe. In specific situations, surgical biopsy may be necessary prior to definitive therapy.
In many cases, small tumors can be observed. Often, however, a diagnosis is necessary and surgical biopsy or resection is warranted. For small tumors in the lateral and third ventricles, direct endoscopic biopsy and resection is possible. However, for larger tumors, a brain-port is helpful for better tumor access and control.
For 4th ventricle tumors, a suboccipital approach is utilized, with endoscopic assistance when necessary. Occasionally, an endoscopic third ventriculostomy is necessary to treat the hydrocephalus while a diagnosis or definitive adjuvant therapy is prepared.