CSF findings in Leptomeningeal Carcinomatosis
Approximately 5% of patients with solid tumors develop leptomeningeal carcinomatosis occurs when solid-tumor cells gain access to the subarachnoid space. The most common solid cancers with leptomeningeal metastases are breast cancer, lung cancer, gastrointestinal cancer, and melanoma.
Signs and symptoms may originate in the cerebrum, cranial nerves, or spinal cord. Cerebral manifestations include headache, seizures, altered mental status, and ataxia. Nausea and vomiting may occur owing to increased intracranial pressure from disrupted CSF flow. Cranial neuropathies are caused by infiltration of nerves crossing the subarachnoid space. Oculomotor, abducens, trochlear, facial, and vestibulocochlear nerves are most commonly affected. Manifestations of spinal involvement range from weakness, paresthesias, and pain to the cauda equina syndrome.
Examination of cerebrospinal fluid (CSF) reveals elevated opening pressure, lymphocytosis, elevated protein concentration, and decreased glucose concentration. Cytology fails to detect tumor cells in 30 to 50% of patients. A second lumbar puncture should be performed if clinical suspicion of leptomeningeal carcinomatosis is high. A second cytologic exam increases sensitivity to approximately 90%.
NEJM Resident e-Bulletin, Teaching Topics, September 1, 2016
