Endoscopic ultrasound elastography for evaluation of lymph nodes and pancreatic masses: a multicenter study.

AIM: To evaluate the ability of endoscopic ultrasound (EUS) elastography to distinguish benign from malignant pancreatic masses and lymph nodes. METHODS: A multicenter study was conducted and included 222 patients who underwent EUS examination with assessment of a pancreatic mass (n = 121) or lymph node (n = 101). The classification as benign or malignant, based on the real time elastography pattern, was compared with the classification based on the B-mode EUS images and with the final diagnosis obtained by EUS-guided fine needle aspiration (EUS-FNA) and/or by surgical pathology. An interobserver study was performed. RESULTS: The sensitivity and specificity of EUS elastography to differentiate benign from malignant pancreatic lesions are 92.3% and 80.0%, respectively, compared to 92.3% and 68.9%, respectively, for the conventional B-mode images. The sensitivity and specificity of EUS elastography to differentiate benign from malignant lymph nodes was 91.8% and 82.5%, respectively, compared to 78.6% and 50.0%, respectively, for the B-mode images. The kappa coefficient was 0.785 for the pancreatic masses and 0.657 for the lymph nodes. CONCLUSION: EUS elastography is superior compared to conventional B-mode imaging and appears to be able to distinguish benign from malignant pancreatic masses and lymph nodes with a high sensitivity, specificity and accuracy. It might be reserved as a second line examination to help characterise pancreatic masses after negative EUS-FNA and might increase the yield of EUS-FNA for lymph nodes.

Solid and pseudopapillary tumor of the pancreas--review and new insights into pathogenesis.

Solid pseudopapillary tumors (SPT) of the pancreas are rare neoplasms that occur mostly in young women. Despite of a low malignant potential, 10% to 15% of the cases have aggressive behavior with metastatic dissemination possibly leading to death. To date, no pathological factor can reliably predict the outcome of these tumours. Galectin-3, a major actor in the carcinogenesis of pancreatic ductal adenocarcinoma, has not been investigated in SPT. The presence of progesterone receptors is frequently reported in SPT, whereas that of estrogen receptor (ER) is unclear. We studied 5 cases of SPT consisting of 4 pancreatic tumors and 1 metastatic case. The morphological distinctive feature of metastatic nodules was the presence of polygonal or spindle cells with pleiomorphic nuclei and high mitotic count exhibiting a diffuse, infiltrative growth pattern. We found a strong expression of galectin-3 in all SPTs, whereas, interestingly, it was lower in metastatic nodules. Conversely, no galectin-3 expression was found in normal pancreatic endocrine cells or in neuroendocrine tumors. We suggest therefore that galectin-3 is a useful marker to distinguish SPT from neuroendocrine tumor, and also indicator of behavior because its low expression is associated with metastatic spreading. Moreover, the presence of galectin-3 in both SPT and pancreatic ducts rises the hypothesis of a posible ductal origin of these tumors. Specific antibodies for anti-ERalpha and anti-ERbeta demonstrated a strong expression of ERbeta whereas ERalpha was not detected. In conclusion, the present study brings the first evidence of the involvement of galectin-3 in SPT but also brought up clues which allowed to reconcile previously conflicting results on the presence of ER.