Response Options to "Histologic grade"
___ GX: Grade cannot be assessed
___ G1: Low grade (carcinoid)
___ G2: Intermediate grade
Grade Mitotic Rate (per 10 HPF) # Ki-67 Index (%)##
G1 <2 ≤2
G2 2 to 10 3 to 20
G3 >10 >20
# Mitotic rate should be based upon counting 50 high-power (40x objective) fields and in the area of highest mitotic activity, and reported as number of mitoses per 10 HPF.
## Ki-67 index is reported as percent positive tumor cells in area of highest nuclear labeling although the precise method of assessment has not been standardized. It has been recommended that 500 to 2000 tumor cells be counted to determine the Ki-67 index. Published criteria that rely upon determination of mitotic count for grading of GI and pancreatic NETs have been reported using counts per high-power field and do not specify microscopic field size or number of mitoses per mm2. Grade assigned based on Ki-67 index may be higher than that based on mitotic count. Thus, reporting the higher grade by either method is preferred if both are performed.
G1 and G2 are well-differentiated tumors with diffuse intense chromogranin/synaptophysin positivity. Punctate necrosis is more typical of G2 tumors. G3 tumors are high-grade neuroendocrine carcinomas (the CAP carcinoma protocol for appendiceal carcinoma should be used for poorly differentiated neuroendocrine carcinomas of appendix).
Response Options to "Microscopic tumor extension"
___ Cannot be assessed
___ No evidence of primary tumor
___ Tumor invades lamina propria
___ Tumor invades submucosa
___ Tumor invades muscularis propria
___ Tumor invades subserosal tissue without involvement of visceral peritoneum
___ Tumor extends into mesoappendix
___ Tumor penetrates serosa (visceral peritoneum)
___ Tumor directly invades adjacent structures (specify: _____________)
___ Tumor penetrates to the surface of the visceral peritoneum (serosa) and directly invades adjacent structures (specify: ______________)