Endoscopic ultrasound for differential diagnosis of focal pancreatic lesions, confirmed by surgery

Background: Endoscopic ultrasound is increasingly used for evaluation of pa ncreatic cancer. The potential of sonographic morphology to differentiate h istology type and biological behaviour of pancreatic lesions is doubtful. M ethods: We prospectively studied 115 patients with focal pancreatic lesions on endoscopic ultrasound. Morphology was assessed using Olympus UM3/20/200 echoendoscopes. Histologic confirmation of diagnosis was obtained in all p atients. Results: Endoscopic ultrasound correctly diagnosed 18/34 benign an d 77/81 malignant lesions. Sensitivity, specificity, accuracy, PPV and NPV for diagnosing malignancy were 95%, 53%, 83%, 83% and 82%, respectively. En dosonographic diagnosis of the lesions (% correct) were: pancreatic cancer, 84 (63.3%); chronic pancreatitis, 14 (71.4%); ampullary cancer, 9 (77.8%); cystadenoma, 5 (80%); ampullary adenoma, 2 (50%); acute pancreatitis, 1 (0 ). In 13 patients of chronic pancreatitis, diagnosed as cancer, diagnosis w as based on absence of sonographic features of chronic pancreatitis (7) or suspected involvement of adjacent structures (6). In 3 patients malignancy was missed owing to features of chronic pancreatitis. Non-suspected neuroen docrine rumours were misjudged in all 10 cases using morphologic criteria a s pancreatic cancer (8), cystadenoma and chronic pancreatitis. Accuracy far prediction of metastatic lymph nodes and an advanced pancreatic cancer sta ge (TxN1 or T3Nx) was 61% and 75%, respectively. On retrospective analysis, a lesion >2 cm, vessel ingrowth, absence of cystic spaces and absence of d iffuse pancreatitis were associated with pancreatic cancer. Conclusions: Wh ile overall sensitivity was high, specificity of endoscopic ultrasound for diagnosis of malignancy was low, especially in presence of chronic pancreat itis. In addition, endosonography had only a limited potential to predict t he histological type of lesions.