Cell blocks in cytopathology: a review of preparative methods, utility in diagnosis and role in ancillary studies

Abstract

The cell block (CB) is a routine procedure in cytopathology that has gained importance because of its pivotal role in diagnosis and ancillary studies. There is no precise review in the published literature that deals with the various methods of preparation of CB, its utility in diagnosis, immunocytochemistry (ICC) or molecular testing, and its drawbacks. An extensive literature search on CB in cytology using internet search engines was performed for this review employing the following keywords: cell block, cytoblock, cytology, cytopathology, methods, preparation, fixatives, diagnostic yield, ancillary and molecular studies. Ever since its introduction more than a century ago, the CB technique has undergone numerous modifications to improve the quality of the procedure; however, the overall principle remains the same in each method. CBs can be prepared from virtually all varieties of cytological samples. In today's era of personalized medicine, cytological specimens, including CBs, augment the utility of cytological samples in analysing the molecular alterations as effectively as surgical biopsies or resection specimens. With the availability of molecular targeted therapy for many cancers, a large number of recent studies have used cytological material or CBs for molecular characterization. The various techniques of CB preparation with different fixatives, their advantages and limitations, and issues of diagnostic yield are discussed in this review.

Comparative study of cell block versus centrifuged smear examination from aspirates of cystic lesions

“…On FNA of cystic lesions, when aspirated fluid is centrifuged, concentration of lesion-typical cells with decreased cell dispersion occurs and improves diagnosis. [19,20] CB procedure of such concentrated material, could replace biopsy thereby simplifying the diagnostic process. [10][11][12] Moreover, material obtained by FNA of some lesions accessed through newer procedures like endoscopy etc., maybe so little that CB on the little material gives added advantage of architectural details and additional material for special stains.…”

Cell-block in EUS Guided FNA-Best method in a Resource Constraint Setting?

“…These automated methods achieve higher cellularity and better cellular presentation in addition it is faster and more reliable due to lack of operator dependency [4,7,8].…”

Cytological Evaluation of Two Methods of Effusion Cell Block Preparations

“…[21,22,23] PT preparation is cost effective, relatively easy and optimal for IHC. [24] They are most useful in CB preparation particularly in effusions with minimal cellularity. [10] Advantages of this method include the assessment of an additional sample volume and thus reduction of sampling error, the possibility for unlimited storage and molecular testing similar to histological samples.…”

“…[10] Advantages of this method include the assessment of an additional sample volume and thus reduction of sampling error, the possibility for unlimited storage and molecular testing similar to histological samples. [24] Additional studies with an in depth analysis to determine the appropriate method(s) is necessary. Determining and standardizing the most effective technique may alleviate the variability and provide consistency.…”