Comparison of World Health Organization 2000/2004 and World Health Organization 2010 classifications for gastrointestinal and pancreatic neuroendocrine tumors (original) (raw)

2015, Annals of Diagnostic Pathology

between 2000 and 2012 were retrieved and reevaluated. Demographic features of the groups were analyzed from the institutional database. Only resection materials were included in the study. Biopsies and metastatic materials were excluded. 2.2. Immunohistochemical Analysis Immunohistochemical analysis of Chromogranin A (LK2H10+ PHE5, Neomarkers), Synaptophysin (27G12, Novacastra), and Neuron-Specific Enolase (Clone E 27, Neomarkers) was used to evaluate for neuroendocrine differentiation. All the cases were diffusely (>%50) and strongly positive for at least two neuroendocrine markers. Ki67 (RM-9106-R7, Neomarkers) immunostaining was performed for the proliferation index. One representative block was selected for Ki-67 index. 2.3. Classification, Grading and Staging The tumors are classified as WDETB, WDETUB,WDEC or PDEC according to the WHO 2000/2004 guidelines. Tumor diameter, localization, depth of invasion (gross local invasion for pancreas) and metastatic state are considered in this classification (Table 1, Table 2, Table 3). All the slides were re-reviewed for prognostic parameters such as angiolymphatic invasion, perineural invasion, necrosis, mitosis; blinded of the original diagnosis. Mitotic count and the ki-67 index were investigated for classifying the cases according to WHO 2010. Counting Ki-67 and mitosis were performed blinded by two pathologists. The mitotic index was expressed as the number of mitoses per 10 HPF (approximately 2 mm²) after evaluating at least 50 HPF (or the entire tumor area in case of small tumors). Proliferation zone cells