Diagnostic pitfalls in effusion fluid cytology

Abstract

Effusion fluid cytology has propensity for both false positives (in up to 0.5%) and false negatives (in up to 30%) results. Methodical approach from collection step to final interpretation stage could prevent both false positives and false negatives, if the interpreter is familiar with various factors responsible for diagnostic pitfalls in effusion fluid cytology. For this discussion, these factors are categorized as mentioned below: Surface tension-related alterations in cytomorphology Improper specimen processing Many faces of reactive mesothelial cells, overlapping with those of cancer cells Proliferation-related features Degenerative changes, such as nuclear hyperchromasia and cytoplasmic vacuolation Unexpected patterns and unusual entities.