According to last week’s webinar led by Balazs Szladovits DVM MRCVS FHEA Diplomate ACVP, the answer to this question is ‘yes’ with the humble egg being used as a perfect example of how smears submitted for cytology can either provide really useful information or offer absolutely nothing in terms of diagnostic value. I realise the use of food in relation to cytology is a lot to get your head around but bear with me as I try to explain. The fried egg represents the perfect cell on a cytology slide. It’s the one which hasn’t been crushed and is clear in this form where the nucleus (yolk) is in correct proportion to the cytoplasm (egg white) and any intracellular inclusions are easily visualised. The cross section of a boiled egg on the other hand, represents the cell which has been compressed by a multitude of other cells as a result of a smear which is just too thick. Finally, the presence of scrambled egg offers the worst-case scenario as it represents cells which have been crushed almost to oblivion due to rough handling. Needless to say, in order for us to get the most out of our cytology preparations we need to be making ‘fried eggs’ to allow pathologists the opportunity to extract as much useful information as possible even if a definitive diagnosis is not always made.
Balazs used last week’s webinar to deliver practical and simple tips on how to obtain the best possible cytology smear and ensure we get those ‘fried eggs’. Performing effective fine needle aspirates (FNAs) was a logical place for Balazs to begin and whether to use a vacuum when performing aspirates was the first question asked. Balazs answered this by advising in around 90% of cases the use of only a small 22-24 gauge needle without a syringe should deliver satisfactory aspirates. The needle should be placed into a mass and redirected several times in order to get a representative sample. If no fluid or tissue is obtained using this technique, a larger needle can be used and if this is still unsuccessful then it may be necessary to apply a vacuum using a 2-3 ml syringe. The expelling of any aspirated material onto a slide is another process which needs to be performed ‘gently’. This is certainly different to the advice I was given many years ago at vet school which taught me to ‘spray’ the aspirated material out as forcefully as possible, a technique which is likely to turn any cells into the dreaded scrambled egg.
Performing a smear is the process which, if done well, will aid in producing those perfect fried eggs. Balazs demonstrated the cross-smear technique where one slide is placed perpendicular to the slide holding the aspirated droplet. This droplet is allowed to disperse and the top slide is then pulled across the bottom slide using gentle pressure. If too much pressure is applied during this process, the cells will rupture and turn into scrambled egg and if too little pressure is applied the smear will be too thick and produce boiled eggs. Balazs also went into some detail about what a smear should look like by showing a number of different slides. Blood contamination, for example, is not really acceptable as any aspirated cells will be heavily diluted with red blood cells and the presence of white blood cells such as neutrophils already in the blood makes interpreting cytology almost impossible. The presence of fat on a slide however is nothing to be concerned about. I know I’m always worried that all the fat and cells will be washed away during the fixing process but in fact the fat will indeed be dissolved by the alcohol but any aspirated cells will remain in place.
For all of you whose heart sinks every time you are informed by a pathologist that your cytology submission offers no useful information in terms of moving forward with a diagnosis, Balazs’ webinar is a must see. It delivers practical and useful tips on how to ensure you get as much out of your cytology as possible and should get you producing beautiful fried eggs every time.