Cell count-based triaging of cytology samples for cell block preparation

Cytology samples can sometimes yield cell blocks of low cellularity that are inadequate for cytomorphological evaluation and ancillary studies. The purpose of this study was to analyse the value of cell count based-triaging of samples for cell block preparation.

Cell blocks were prepared from different cytology samples using HistoGel™ according to the manufacturer's instructions following cell count assessment. The adequacy of cell blocks was semi-quantitatively scored as empty, scanty, moderate or highly cellular by evaluating corresponding haematoxylin and eosin (H&E) sections. Cell blocks with moderate and highly cellular H&E sections were considered adequate whereas cell blocks with empty and scanty cells in H&E sections were inadequate for cytomorphological evaluation. The average, range and a median number of cells (×10⁶ ) embedded in adequate and inadequate cell blocks were compared.

Among 54 cell blocks prepared from fine needle aspiration biopsies (FNAs, 32), effusions (4), brushings (13) and cell lines (5), 20 cell blocks (37%) yielded moderate or highly cellular H&E sections and were considered adequate whereas 34 (63%) cell blocks were empty or scanty and thus considered inadequate. The average (± SD) number of cells (×10⁶ ) embedded in adequate and inadequate cell blocks was 2.1 ± 4.3 and 0.5 ± 0.3, respectively. Samples containing at least 1 × 10⁶ cells yielded adequate cell blocks in 12/16 cases (75%) whereas samples with less than 1 × 10⁶ cells in 13/38 (34%) cases.

The present study showed that cell count-based triaging of cytology samples could reduce the number of low cellular cell blocks.