Neuroendocrine Cancer of Rectum Metastasizing to Ovary

Table 1

Compiled classification and nomenclatures of NENs.

Traditional nomenclature based on grades of differentiation and histopathology		WHO; ENETs classification of NENs			Accepted nomenclature
		Types	Mitotic index; per 10 high power fields (HPF)	Immunohistochemistry; Ki 67 index
Low	Carcinoid tumor	Neuroendocrine tumor (NET), grade 1	<2	<3%	Well-differentiated neuroendocrine tumor (WD-NET) May be functional (F) or nonfunctional (NF)
Intermediate	Atypical carcinoid tumor	Neuroendocrine tumor (NET), grade 2	2–20	3–20%
High	Small-cell carcinoma; Large-cell neuroendocrine carcinoma (NEC)	NEC grade 3, small-cell carcinoma; NEC grade 3, large cell neuroendocrine carcinoma	>20	>20%	High grade neuroendocrine carcinoma (HG-NEC) (F or NF)