Liquid Based Preparation (LBP) cytology versus Conventional Cytology (CS) in FNA samples from breast, thyroid, salivary glands and soft tissues. Our experience in Crete (Greece).

Background: The improvement in quality of cytological preparations with the use of LBP methodology has been well-documented, but the cytological artifacts resulting from this technique have not been adequately described. This study describes and illustrates the cytological artifacts introduced by LBP technique when used on fine-needle aspirates (FNAs), and evaluates these artifacts as potential diagnostic pitfalls.

Study Design: We reviewed a total of 96 FNAs simultaneously processed by both conventional smears and LBP. FNAs were obtained from the following sites: lymph node (38), breast (28), soft-tissue sites (nine), salivary glands (six), and thyroid gland (15).

Results: The LBP smears were consistently devoid of obscuring elements, and the cells were adequately preserved and evenly dispersed. However, we noted some cytomorphological alterations that should be recognized to avoid erroneous diagnoses. The size of cell clusters was decreased, large branching sheets were fragmented, and there were more single cells, resulting in apparent discohesion. Small cells such as lymphocytes tended to aggregate. All cells were generally smaller and occasionally spindled, the chromatin detail was attenuated, and nucleoli were more prominent. Intranuclear inclusions were difficult to visualize. Background matrix was often altered in both quantity and quality. Extracellular particles, small mononuclear cells, red blood cells, and myoepithelial cells were markedly decreased in number.

Conclusions: Cytopathologists should be careful in interpreting FNAs prepared using LBP technique if that is the only methodology employed. Familiarity with artifacts is essential to avoid misdiagnoses.