The interaction between tumor cells and inflammatory cells has an important role in cancer initiation and progression; however, this interaction has not been systematically investigated in pancreatic neoplasia. In this study, the presence of tumor-infiltrating neutrophils within and/or adjacent to neoplastic cells was investigated in pancreatic neoplasms. Areas with >10 tumor-infiltrating neutrophils/100 epithelial cells were arbitrarily classified as positive. Those with 11–15 tumor-infiltrating neutrophils were considered ‘borderline’ while those with >15 tumor-infiltrating neutrophils were considered ‘significant’. Among 363 invasive ductal carcinomas, 15 showed significant tumor-infiltrating neutrophils (8 were micropapillary carcinomas and 7 were undifferentiated carcinomas). Of 19 mucinous cystic neoplasms with a carcinomatous high-grade papillary component, 11 showed significant tumor-infiltrating neutrophils (mean, 25; range, 14–63 tumor-infiltrating neutrophils). Among intraductal papillary mucinous neoplasms, significant tumor-infiltrating neutrophils were identified in 4/16 pancreatobiliary type, but were uncommon in other types (1/11 oncocytic and 1/23 intestinal types had borderline tumor-infiltrating neutrophils, and 0/10 gastric type had tumor-infiltrating neutrophils). Non-carcinomatous (low-grade and non-papillary) components of these neoplasms did not have tumor-infiltrating neutrophils. Tumor-infiltrating neutrophils were not striking in neuroendocrine tumors (40), serous cystadenomas (18), acinar cell carcinomas (9) or solid-pseudopapillary neoplasms (8). In conclusion, significant tumor-infiltrating neutrophils are uncommon in pancreatic ductal adenocarcinoma, and when they occur it is typically in the micropapillary and undifferentiated types with a known poor prognosis. Among pre-invasive neoplasia, tumor-infiltrating neutrophils show a predilection for papillary in-situ carcinomas of mucinous cystic neoplasms, or less commonly, pancreatobiliary-type intraductal papillary mucinous neoplasms (both of which express cell surface-associated mucin 1 (MUC1)). MUC1 expression by these tumors may have biologic implications, considering its recently established relationship with inflammatory cells in carcinogenesis, and the differential expression of mucins in pancreatic neoplasia. Larger studies are needed to investigate the association between tumor-infiltrating neutrophils and pancreatic neoplasms and their role in their clinical behavior.

Tumor differentiation can be used to guide selection of nuclear imaging modalities for staging gastrointestinal and pancreatic NETs. Octreoscan appears more sensitive than (18)FDG-PET for well-differentiated NETs, whereas (18)FDG-PET demonstrates superior sensitivity for poorly-differentiated NETs.

Lymph node status is one of the most important predictors of survival in resectable pancreatic ductal adenocarcinoma; therefore, thorough lymph node evaluation is a critical assessment in pancreatoduodenectomy specimens. There is considerable variability in pancreatoduodenectomy specimens processed histologically. This study compares two approaches of lymph node dissection and evaluation (standard vs orange peeling) of pancreatoduodenectomy specimens. A different approach to dissection of pancreatoduodenectomy specimens was designed to optimize lymph node harvesting: All peripancreatic soft tissues were removed in an orange-peeling manner before further dissection of the pancreatic head. This approach was applied to 52 consecutive pancreatoduodenectomy specimens performed for ductal adenocarcinoma at two institutions. Specimen dissection was otherwise performed routinely. Overall number of lymph nodes harvested, number of positive lymph nodes, and their anatomic distribution were analyzed and compared with cases that had been dissected by the conventional approach. The mean number of lymph nodes identified by the orange-peeling approach was 14.1 (by institution, 13.8 and 14.4), as opposed to 6.1 (by institution, 7 and 5.3) in cases processed by conventional approach (P=0.0001). The number of lymph node-positive cases also increased substantially from 50% (by institution, 54 and 46%) in the conventional method to 73% (by institution, 88 and 58%) in the orange-peeling method (P=0.02). The orange-peeling method of lymph node harvest in pancreatoduodenectomy specimens for ductal adenocarcinoma enhances overall and positive lymph node yield and optimizes ductal adenocarcinoma staging. Therefore, lymph node harvest by the orange-peeling method should be performed routinely before specimen sectioning in assessment of pancreatoduodenectomy for ductal adenocarcinoma.

Molecules implicated in clear-cell tumorigenesis are also consistently expressed in SCA. This may have biologic and therapeutic implications, especially considering the rapidly evolving drugs against these pathways. More importantly, SCA may also serve as a model of clear-cell-associated angiogenesis and tumorigenesis, and the information gained from this tumor type may also be applicable to other clearcell tumors.