Neoplastic meningitis is caused by another tumor seeding into the CNS Cancer from a distant source enter the CSF by means of the following:  Hematogenous Spread from a distant primary tumor site - cancer cells produce enzymes that allows them to microscopically invade blood vessels to reach the subarachnoid space through the systemic arterial circulation or by the Batsons venous plexus. Invasion from a primary brain tumor to the meninges - when cancer cells lodge into small arteries causing local ischemia and blood vessel damage leading to spillage of neoplastic cells to the Virchow-Robin spaces thereby providing access to the subarachnoid space. Infiltration to the spinal cord - Cancer cells gain access to the subarachnoid space through this route via the perivascular tissues the surround the blood vessels at the brain entrance. Direct infiltration of the spinal nerve roots (dorsal and ventral) has also been documented. Cancer spread a neural pathways to reach the meninges - The CSF carries cancer cells through the brain tracts. This occurs mostly in tumors of the head and neck.  Iatrogenic - from surgical procedures involving removal of a primary brain tumor Primary neoplastic meningitis has also been documented particularly with melanoma.
What causes Neoplastic meningitis?
Neoplastic meningitis is caused by another tumor seeding into the CNS Cancer from a distant source enter the {{ORGANIZATION}} by means of the following:  Hematogenous Spread from a distant primary tumor site - cancer cells produce enzymes that allows them to microscopically invade blood vessels to reach the subarachnoid space through the systemic arterial circulation or by the Batsons venous plexus. Invasion from a primary brain tumor to the meninges - when cancer cells lodge into small arteries causing local ischemia and blood vessel damage leading to spillage of neoplastic cells to the Virchow-Robin spaces thereby providing access to the subarachnoid space. Infiltration to the spinal cord - Cancer cells gain access to the subarachnoid space through this route via the perivascular tissues the surround the blood vessels at the brain entrance. Direct infiltration of the spinal nerve roots (dorsal and ventral) has also been documented. Cancer spread a neural pathways to reach the meninges - The {{ORGANIZATION}} carries cancer cells through the brain tracts. This occurs mostly in tumors of the head and neck.  Iatrogenic - from surgical procedures involving removal of a primary brain tumor Primary neoplastic meningitis has also been documented particularly with melanoma.