Characterizing specimen quality of cell block samples in an era of personalized diagnostics: analysis of 221 lymph node fine-needle aspirations.

ABSTRACT

INTRODUCTION: Cell block (CB) preparations of fine-needle aspirates (FNAs) are utilized for patient management, which requires retention of representative material on slides. Personalized medicine demands quality CB specimens. There is no standard protocol for CB preparation, often resulting in suboptimal slides. The utility of using two CB slides in lymph node (LN) FNA cases was investigated. MATERIALS AND METHODS: We cut 10 serial sections from each CB, slides 1 and 5 are stained and considered the first and second cuts, respectively; the remaining slides are reserved for ancillary studies. Hematoxylin and eosin-stained CBs of 221 consecutive LN FNA cases were reviewed; qualitative and quantitative assessment of diagnostic value was made on sections 1 and 5. RESULTS: Of the 221 cases, 46.1% (102) had comparable diagnostic cellularity (equally representative) on both slides, whereas 26.7% (59) and 27.1% (60) had more representative material on the first and second cuts, respectively (P = 0.52). Differences between the representativeness of first and second CB cuts of intrathoracic lymph nodes were minor (n = 192, P = 0.065). Differences between the first and the second slide representativeness of superficial (n = 22, P = 0.98) and intra-abdominal lymph nodes (n = 7, P = 0.38) are limited because of small sample sizes. CONCLUSION: One CB cut can be suboptimal for diagnosis. In our study, inclusion of a second slide increases equal representativeness from 46.1% to 73.2%. These limited observations recognize the need for additional investigations regarding the collection and preparation of CBs.