Fine-needle aspiration: comparison of smear, cytospin, and cell block preparations in diagnostic and cost effectiveness

Contemporary art of cell-block preparation: Overview

Cell blocks (CBs) are paraffin-embedded versions of cytology specimens. These versions are contrasted with tissues made from surgical pathology specimens of formalin-fixed paraffin-embedded (FFPE) tissue. CBs enable various elective ancillary studies of a range of specimens. These studies include the potential to perform molecular tests with the enhanced cytopathological interpretation. CBs are increasingly reported in cytology specimens. The enhanced role of CBs incorporates additives with new markers for immunohistochemistry (IHC), including the multicolored approach to IHC, and the subtractive coordinate immunoreactivity pattern. Even when archived material is retrospectively retrieved, CBs are a major tissue source for many supplementary studies. The CBs have been qualitatively and quantitatively improved. CBs are significant since they have increased molecular markers standardized on FFPE tissue. High-quality CBs can serve as useful additions to cytological smear preparations and touch imprint cytology. Most cytological specimens, such as fine-needle aspirations, cavitary effusion, washings, brushings, and gynecological and non-gynecological liquid specimens, may be used to produce CBs. This review deals with the CB-making process and discusses various historical limitations with an emphasis on recent advances.

Diagnosis of pancreatic tumors by endoscopic ultrasound-guided fine-needle aspiration

AIM: To evaluate the diagnostic accuracy of endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) for pancreatic solid tumors larger or smaller than 3 cm, and cystic lesions.

METHODS: From January/1997 to December/2006, 611 patients with pancreatic tumors were subjected to EUS-FNA. The final diagnosis was obtained either by surgery (356 cases) or after a mean clinical follow-up of 11.8 mo in the remaining patients.

RESULTS: There were 405 solid tumors, 189 cystic lesions and 17 mixed. Pancreatic specimens for cytological assessment were successfully obtained by EUS-FNA in 595 (97.4%) cases. There were 352 (57.6%) malignancies and 259 (42.4%) benign tumors. Among the malignancies, pancreatic adenocarcinomas accounted for 67% of the lesions. Overall, the sensitivity, specificity, positive and negative predictive values, and accuracy of EUS-FNA were, respectively, 78.4%, 99.2%, 99.3%, 77.2% and 87.2%. Specifically for solid tumors, the same parameters for neoplasms larger and smaller than 3 cm were, respectively, 78.8% vs 82.4%, 100% vs 98.4%, 100% vs 99%, 54.8% vs 74.1% and 83.1% vs 87.8%. For cystic lesions, the values were, respectively, 72.2%, 99.3%, 97.5%, 91% and 92.2%.

CONCLUSION: EUS-FNA can be used to sample pancreatic tumors in most patients. Even though the negative predictive value is inadequate for large solid tumors, the results are rather good for small solid tumors, especially concerning the sensitivity, negative predictive value and diagnostic accuracy. Among all pancreatic lesions, EUS-FNA for cystic lesions can reveal the best negative predictive value and diagnostic accuracy, both higher than 90%.