4548 Role of endosonography guided fine needle aspiration biopsy in pancreatic cysts.

Abstract

Accuracy of endosonography (EUS) in the differential diagnosis of pancreatic cystic lesions may possibly be improved by fine needle aspiration biopsy (FNAB). From July 97 until Nov 99, 73 patients underwent EUS guided FNAB for pancreatic cystic lesions with a overall diagnostic accuracy of EUS of 80.2%. Of these series, 36 patients underwent full assessment including EUS evaluation, cytology and biochemistry of the cystic fluid (amylase, lipase, CEA and CA199). Methods: Mean age was 59.5 y (range 33-78), 17 women and 19 men. Mean lesion size was 37 mm (9-100). EUS was performed under sedation with midazolam and antibiotics were given for 5 days. Cytology specimens were methanol fixed smears and cytocentrifuged cell suspensions stained with Papanicolaou method. Final diagnosis was obtained by surgery (7), endoscopy(4) or follow-up (25):13.5 (range 1-42)months and consisted into 9 malignant cysts (8 ADC and 1 cystic endocrine tumour), 11 serous cystadenoma (SC), 3 mucinous cystadenoma (MC), 11 pseudocysts (PC) and 2 others (lymphangioma and mesothelial cyst). Results: EUS correctly identified 33/36 cysts (accuracy of 88.9%): errors were 1 MC, 1 CS and 1 PC. Cytology correctly identified all lesions except 1 MC (diagnosed as a serous cyst); accuracy was thus 35/36, 97.2%. Biochemistry was accurate in 28/36,77.7%: amylase levels were (UI/L mean, range):79 (5-8014) in ADC, 1750 (4-6160) in MC, 71 (22-2000) in SC, 34050 (487-255500) in PC and 0-27 in others. CEA levels (ng/ml)were: 1409 (0.2-24247) in ADC, 724 (24-59794) in MC, 3.4 (2.7-900) in CS and 0-4.2 in others. CA199 levels (U/ml) were: 999990 (12-2400000) in ADC, 574219 (250-999999) in MC, 264 (5-78574) in SC, 23730 (9-2234766) in PC and 0- 26.5 in others. With the following criteria: MC or ADC= CA199 >50000; CS= CEA 5000, biochemistry failed in 2 malignant cysts (CA199 of 12 [endocrine] and 25254), 1 MC (CA199 of 250), 1 PC (amylase: 487), and 4 SC (CEA: 14, 159, 180 and 22.3). The lesions where biochemistry showed discrepancy were very small (mean size 11.3 mm), a longer follow-up would probably be necessary in these cases. According to the final diagnosis, accuracy was 97.2 % for the combination of all techniques with no false negative result. Complications (sepsis) were reported in 2/73 pts (0/36)and treated medically or by endoscopy. Conclusion: combination of EUS, cytology and biochemical analysis yields an overall accuracy of 97% in pancreatic cystic lesions, with few side effects, allowing to avoid surgical diagnostic procedures in most of the cases.