A New Cytology Staining Method: A Fast Approach for Rapid On-Site Evaluation on Thyroid Fine-Needle Aspiration Cytology

INTRODUCTION

Thyroid fine-needle aspiration (FNA) is a well-established technique in the cytology literature. Through the introduction of rapid stains in cytology practice, the ever-increasing utility of rapid on-site evaluation (ROSE) has strengthened the place of FNA as a primary diagnostic method in patient management. There are few stain variants available in the market for ROSE, namely Diff-Quik (DQ), Toluidine blue, and ultrafast Papanicolaou stains. Recently, our group developed a new staining variant labeled as original "BlueStain®" technique that was not previously tested in this context.

METHODS

40 FNA thyroid cases were studied. At least two slides were prepared from each patient: one stained by DQ and the other by BlueStain®. Simultaneously, a ROSE diagnosis was performed as the two staining methods were compared, evaluating the parameters of background, cellularity, details of colloid presence, cell morphology, nuclear details, cytoplasmic details, and overall staining, scored on a scale from 1 to 3, representing poor, average, and good, respectively.

RESULTS

The quality index was slightly better for BlueStain® (53% vs. 47%) but not significantly different between the two stains. BlueStain® provides better details in both the presence and type of colloid as well as nuclear details, which are regarded as very important for diagnosis in thyroid cytology. There were eight cases with discordant diagnosis when compared between two stains from the same patient. In five cases of indeterminate cases, BlueStain® allows to bring them to the benign category, probably because this staining method allows a clear observation of the colloid in the background of the smears. However, since we are observing two different slides, we cannot rule out that these differences are a question of sample collecting and/or smearing.

CONCLUSIONS

Our data demonstrates that BlueStain® is suitable to provide good-quality slides for primary assessments of thyroid aspirates studied by ROSE. In fact, in some aspects, this new staining method shows better preservation of colloid and cell details, revealing itself as an alternative to the DQ stain variant, upholding performance level while being 10 times cheaper and simpler because it requires just one step of staining.

Modified PNA Telomere and Centromere FISH Protocols

Fluorescence in situ Hybridization (FISH) utilizes peptide nucleic acid (PNA) probes to identify specific DNA sequences. PNA probes have been effectively used to identify chromosome aberrations and have been shown to greatly aid in biodosimetery assays involved in identifying dicentrics. Traditional techniques have required the heat denaturing of the DNA in formamide followed by multiple hours at moderated temperatures to allow the probe to hybridize to its specific target. Over the past 30 years, advancements in both protocols and probes have made FISH a more reliable technique for both biological research and medical diagnostics, additionally the protocol has been shortened to several minutes. We will introduce two modified PNA FISH protocols, a rapid microwave-based approach and nonclassical hybridization protocol.

Utility of Modified Ultrafast Papanicolaou Stain in Cytological Diagnosis

INTRODUCTION

Need for minimal turnaround time for assessing Fine Needle Aspiration Cytology (FNAC) has encouraged innovations in staining techniques that require lesser staining time with unequivocal cell morphology. The standard protocol for conventional Papanicolaou (PAP) stain requires about 40 minutes. To overcome this, Ultrafast Papanicolaou (UFP) stain was introduced which reduces staining time to 90 seconds and also enhances the quality. However, reagents required for this were not easily available hence, Modified Ultrafast Papanicolaou (MUFP) stain was introduced subsequently.

AIM

To assess the efficacy of MUFP staining by comparing the quality of MUFP stain with conventional PAP stain.

MATERIALS AND METHODS

FNAC procedure was performed by using 10 ml disposable syringe and 22-23 G needle. Total 131 FNAC cases were studied which were lymph node (30), thyroid (38), breast (22), skin and soft tissue (24), salivary gland (11) and visceral organs (6). Two smears were prepared and stained by MUFP and conventional PAP stain. Scores were given on four parameters: background of smears, overall staining pattern, cell morphology and nuclear staining. Quality Index (QI) was calculated from ratio of total score achieved to maximum score possible. Statistical analysis using chi square test was applied to each of the four parameters before obtaining the QI in both stains. Students t-test was applied to evaluate the efficacy of MUFP in comparison with conventional PAP stain.

RESULTS

The QI of MUFP for thyroid, breast, lymph node, skin and soft tissue, salivary gland and visceral organs was 0.89, 0.85, 0.89, 0.83, 0.92, and 0.78 respectively. Compared to conventional PAP stain QI of MUFP smears was better in all except visceral organ cases and was statistically significant. MUFP showed clear red blood cell background, transparent cytoplasm and crisp nuclear features.

CONCLUSION

MUFP is fast, reliable and can be done with locally available reagents with unequivocal morphology which is the need of the hour for a cytopathology set-up.