Cell block technique and cytological smears for the differential diagnosis of pancreatic neoplasms after endosonography-guided fine-needle aspiration.

Cytological smear is widely employed to analyse specimens obtained from endosonography-guided fine-needle aspiration (EUS-FNA), but false-negative or inconclusive results may occur. A better diagnostic yield can be obtained from processing cell blocks. We compared the effectiveness of the cell block technique and cytological smear in the diagnosis of pancreatic neoplasms. From January 1997 to December 2006, 611 patients with pancreatic tumors were evaluated by EUS-FNA. Surgery was performed in 356 cases, and the other 255 patients were followed clinically for an average of 12.8 months. In total, 282 (46.2%) patients were evaluated with cytological smears, and 329 (53.8%) were evaluated using only cell blocks. Malignant disease was detected in 352 (57.6%) cases, in which adenocarcinoma accounted for 236 (67%) cases. A benign disease was found in the other 259 cases, including 35.1% focal chronic pancreatitis and 32.4% pseudocysts. Aspiration samples were satisfactory in 595 (97.4%) patients after an average of 2.2 (1-4) passes of the needle. Regardless of the cytopathological examination technique, EUS-FNA confirmed malignancy in 269 of 352 (76.4%) cases, and a benign disease in 257 of 259 (99.2%) cases. For patients who received surgery with histologically confirmed lesions, the sensitivity specificity, positive and negative predictive values, and accuracy of the smears versus cell blocks in diagnosing pancreatic tumors were 61% versus 85.2% (P<0.001), 100% versus 93.1%, 100% versus 98.4%, 36% versus 55.1% (P=0.046) and 68% versus 86.5% (P<0.001), respectively The cell block technique demonstrated a hig her sensitivity, negative predictive value and accuracy than cytological smears.

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%.