The Cytology Specimen and Preparations: Advantages and Limitations

Abstract

Cytology samples offer a versatile option to tissue specimens for providing material for molecular analysis. Since the use of minimally invasive methods is increasing, so is the number of limited or small specimens, and the cytopathologist must be aware of the particular characteristics of using these specimens (guiding the management of preparations in order to optimize DNA quality and yield) and at the same time adapt to judicious use of cytologic preparations. Many options are available for use in molecular studies, from formalin-fixed paraffin-embedded cell block preparations to smears, cytospins, liquid-based preparations, and even fresh cells. The rational use of this array of different preparations allows not only to establish a proper and definite diagnosis but also to maximize the availability of adequate amounts of high-quality material for nucleic acid extraction. In addition, a variety of cytology preparations provide less degraded material, faster fixation, as well as the option of immediate assessment, what ensures cellular adequacy and appropriate triaging of the sample, as opposed to histology samples. The current chapter envisions, therefore, to outline the main advantages and limitations of cytology specimens for molecular tests when compared to surgical biopsies, discuss the appropriate handling of these samples, describe the main differences among the multiple cytologic preparations, and discuss ways to minimize the limitations in order to achieve an optimal analysis.