Neoplastic meningitis is a medical condition that occurs when cancer cells spread to the membranes surrounding the brain and spinal cord. It can result in symptoms like headaches, nausea, vomiting, and seizures. There are various synonyms used to describe this condition, including leptomeningeal carcinomatosis, meningeal metastasis, and metastatic meningitis. Leptomeningeal carcinomatosis specifically refers to cancer cells spreading to the leptomeninges, which are the thin layers of tissue that cover the brain and spinal cord. Meningeal metastasis is a broader term that describes cancer cells spreading to any part of the meninges. Metastatic meningitis is another general term used to describe cancer cells spreading to the meninges from another part of the body.