Leptomeningeal metastases (LM), is a diffuse dissemination of tumor cells into the cerebrospinal fluid (CSF) and leptomeninges.[1] Up to 8% of all patients with cancer develop LM. Gadolinium enhanced MRI of the symptomatic location of the nervous system is the radiological method of choice when LM is clinically suspected. In patients with a metastasized tumor, based on clinical signs of LM and contrast enhancement of either the leptomeninges, pia mater/cortex or cranial or spinal nerves on MRI, the diagnosis LM can be made. The sensitivity of MRI with gadolineum for LM is 75% and the specificity 77%. If MRI does not show equivocal abnormalities, CSF cytology needs to be performed. In 55% of patients with LM from solid tumors, malignant cells are found during the first CSF examination. The sensitivity raises to 80-90% after the second CSF sampling, as determined in the pre-MRI era. The volume of sampled CSF determines partly the sensitivity of CSF cytology. If possible, 10 ml CSF needs to be taken and the material must be processed as quickly as possible.