Rectal Carcinoid / Well Differentiated Endocrine Neoplasm
Grading / Staging
- Histopathologic features are predictive of behavior (based on AFIP; WHO does not give a concise summary)
- Benign (but note that there are rare reports of mets)
- Non-functioning
- Well differentiated
- ≤2 cm in greatest dimension
- Confined to mucosa and submucosa
- No involvement of muscularis propria
- No vascular invasion
- Uncertain malignant behavior
- Low grade malignant
- Non-functioning and well differentiated, with
- Invasion of muscularis propria or beyond and/or
- Metastasis and/or
- >2 cm in greatest dimension and/or
- >2 mitotic figures per HPF (in WHO but not in AFIP)
- OR, functioning and well differentiated
- Poorly differentiated neuroendocrine carcinoma is covered separately
- AJCC TNM 7th edition now includes carcinoids of the rectum
