Primary pancreatic lymphoma is a rare type of cancer, that accounts for 0.1-0.5% of lymphomas and about 0.2% of all primary pancreatic tumors. Diffuse Large B-cell Lymphoma is the most common subtype. The diagnosis is possible if the lymphoma is located in the pancreas, but the differential diagnosis with pancreatic ductal adenocarcinoma is difficult. The diagnostic accuracy of endosonography-guided fine needle aspiration is inadequate, and thus it is common to diagnose these masses only after surgical resection. The endosonography-guided tissue acquisition allows greater accuracy in the pancreatic masses, as it determines optimal access to histological analysis using tissue in paraffin blocks for complementary immunohistochemical, and molecular tests. Thus, this elaborate diagnostic environment allows the adoption of appropriate treatment strategies for patients with this condition. The authors describe four cases of primary pancreatic lymphoma indicated for surgical resection due to suspected pancreatic cancer, with the diagnosis of Diffuse Large B-cell Lymphoma obtained by endosonography-guided tissue acquisition, changing the therapeutic strategy through the adoption of adequate chemotherapy treatment with good progress.

Objectives: Compare the 22G needle versus EchoTip ProCore® 20 (Cook Medical, Bloomington, IN, USA) on their handling, specimen suitability, amount of tissue obtained, diagnostic performance, the possibility of immunohistochemistry, and rate of adverse events. Materials and methods: This is a retrospective, comparative study of consecutively examined patients with pancreatic masses who underwent endosonography-guided fine needle aspiration (FNA) via the 22G needle, and endosonography-guided tissue acquisition (TA) via ProCore 20 (PC20). The operator evaluated needle insertion and subjectively classified the specimen. The pathologist measured the samples, classified the amount of tissue, and determined the influence of bleeding on the interpretation.Results: A total of 129 patients participated in the study, out of whom 52 underwent endosonographyguided FNA with 22G and 77 underwent endosonography-guided TA with a PC20 needle. Malignant lesions were found in 106, and 23 had benign lesions. The duodenal route was used in 62% of patients. The 22G needle was easier to introduce (p=0.0495). However, PC20 obtained a larger amount (p<0.01) with fewer punctures (p<0.001). The PC20 also yielded a larger average microcore diameter (p=0.0032). Microhistology was adequate for 22G and PC20 in 22 (42.2%) and 50 (78.1%) specimens, respectively (p<0.001). Bleeding was not significantly different (p>0.999). Immunohistochemistry was possible in 36 (69.2%) and 40 (51.9%) specimens obtained by 22G and PC20, respectively (p=0.075). The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of 22G were 93.5%, 100%, 100%, 66.7%, and 94.2%, respectively; and for PC20, it was 95%, 100%, 100%, 85%, and 96.1%, respectively. Mild bleeding was the most common early adverse event, occurring in 2/52 (3.8%) 22G and 4/77 (5.2%) PC20 cases (p>0.05).Conclusions: The PC20 required fewer punctures and reduced the need for immunohistochemistry as it yielded better and larger microcores. Its ease of insertion into the target lesion makes it a good option to obtain satisfactory microcore specimens in difficult positions, such as the transduodenal route.