Background: Body cavity fluids are among the most frequently examined samples in cytology. Cytomorphology is supplemented by additive testing. An international system of terminology and classification has been recently presented.
Objectives: Cytopreparation and staining techniques as well as some exemplary morphological patterns are presented. "The International System for Serous Fluid Cytopathology" (TIS) is briefly presented.
Materials and methods: Pleural effusion, pericardial effusion, and ascites: special technical issues, immunocytochemistry, molecular diagnostics, and reporting system issues are discussed.
Results: Body cavity fluids are important samples that provide significant information. Additive testing is established for routine use. The form and structure of reports is widely divergent in practical use.
Discussion: A reporting system for serous fluid cytopathology that is easily applied and recognized internationally is highly desirable. TIS is a valuable approach to this goal.