TY - JOUR T1 - How to do it: How to get the most out of cerebrospinal fluid cytology JF - Practical Neurology JO - Pract Neurol SP - 241 LP - 243 DO - 10.1136/practneurol-2012-000264 VL - 12 IS - 4 AU - Philip Milburn-McNulty AU - Benedict Michael AU - Neil Moxham AU - Nicholas Fletcher AU - Daniel Crooks Y1 - 2012/08/01 UR - http://pn.bmj.com/content/12/4/241.abstract N2 - Leptomeningeal carcinomatosis, characterised by infiltration of neoplastic cells in the central nervous system (CNS), is rapidly progressive and fatal. It may develop from a neoplasm arising from leptomeningeal cells, such as leptomeningeal-melanocytosis, or by infiltration from a neoplasm from outside the CNS.1 This may be from direct local extension, haematogenous spread or migration along perineural or perivascular spaces.2 The prognosis is extremely poor, with a median overall survival from diagnosis typically less than 3 months.3 Cytological examination of the cerebrospinal fluid (CSF) is the gold standard diagnostic test but its sensitivity varies between 54 and 97%.4,–,10 With such a poor prognosis, prompt diagnosis is important so that appropriate palliative care can be started with minimal delay. We present the factors that maximise CSF cytology sensitivity and provide a strategy to improve practice. When to perform CSF cytology Leptomeningeal carcinomatosis presents with a wide spectrum of neurological symptoms, ranging from confusion through to ataxia, seizures and eventually coma.1 The clinical features include signs of raised intracranial pressure, focal weakness, and isolated or progressive cranial nerve palsies, reflecting basal meningeal infiltration.1 ,2 Up to 19% of patients with known malignancy presenting with neurological symptoms or signs … ER -