A Superior Technique for Cell Block Preparation for Fine Needle Aspiration
Ronald Balassanian, Jill C Ono, Geoffrey D Wool, Jolanta Olejnik-Nave, Molinda M Mah, Brenda J Sweeney, Britt-Marie Ljung, Martha B Pitman. University of California San Francisco, San Francisco, CA; Laboratory Medicine Consultants, Las Vegas, NV; Massachusetts General Hospital, Boston, MA
Background: Cell blocks (CB) from fine needle aspiration biopsies (FNAB) are useful for diagnosis and ancillary studies. Variability in CB techniques can affect diagnostic quality. We describe 3 techniques for CB preparations and performed a statistically validated comparison to determine which system reliably produced the highest quality CB.
Design: We compared 3 CB techniques: 1) The FNAB is rinsed in saline (SR), centrifuged to a pellet, the supernatant is removed and plasma and thrombin are added to form a clot which is submitted to histology. 2) The FNAB needle is rinsed in formalin, centrifuged to a pellet, the supernatant is removed and Histogel™ (HG) is added to form a clot which is submitted to histology. 3) The FNAB is rinsed in formalin, transferred to a test-tube lined by collodion™ polymer, which forms a “collodion-bag” (CLB) membrane, the sample is centrifuged, the bag is removed and tied with a string around the resulting pellet. All samples were submitted to histology in cassettes for routine processing. Four FNAB were performed with standardized technique, on 35 random gross surgical pathology specimens: 1 for direct smears to assess the overall cellularity, and 1 for each of the 3 CB techniques. Blinded review of H&E stained CB slides was performed by 2 pathologists (RB, JO). Each CB slide was scored for cellularity, preservation and architecture, on a scale of 1-3, and the overall best CB was identified. Standard of deviation (SD) and p values were calculated for each category.
Results: Surgical pathology specimens included benign tissue, carcinomas, sarcomas and lymphomas. Mean cellularity score for SR was 1.71 (SD=0.89), for HG was 1.68 (SD=0.67) and for CLB was 3.0 (SD=0). Mean preservation score for SR was 1.31 (SD=0.58), for HG was 1.54 (SD=0.70) and for CLB was 2.91 (SD=0.37). Mean architecture score for SR was 1.45 (SD=0.70), for HG was 1.43 (SD=0.60) and for CLB was 2.71 (SD=0.57). There was no statistical significance between SR or HG when compared for each category. CLB was superior to both SR and HG when compared for each category (p<0.05). The overall best CB was obtained with CLB in 33/35 (94%), with SR in 1/35 (3%) and with HG in 1/35 (3%).
Conclusions: CLB is superior for CB preparation and yields greater cellularity, preservation and architecture in most cases. Our samples were obtained from bench specimens; however standardization in the FNAB technique suggests these results may be extrapolated to patient samples.
Tuesday, March 5, 2013 2:30 PM
Proffered Papers: Section C, Tuesday Afternoon