Standardizing the unstandardized: The international system reaches the cerebrospinal fluid

Two new studies now make the most substantial case yet that the framework of the International System for Reporting Serous Fluid Cytopathology can be carried across the biologic boundary to include cerebrospinal fluid, and current work on the second edition of the system will address cerebrospinal fluid for the first time as a special category of body fluid-an expansion the international community has explicitly endorsed. The contributions of these authors will stand among the empirical foundations on which a coherent, cerebrospinal fluid-specific-and, ultimately, fluid-agnostic-reporting standard can be built.