Specific features of low-grade and high-grade endometrial carcinomas developing during menopause
| Feature | Low-grade endometrial carcinoma | High-grade endometrial carcinoma |
| Age | Perimenopausal and postmenopausal years | Perimenopausal and postmenopausal years |
| Tumour-free endometrium adjacent to carcinoma | Atrophic (but not inactive); usually weakly proliferative | Atrophic (but not inactive); usually weakly proliferative |
| Pathogenesis | Extra-ovarian oestrone stimulation | Extra-ovarian oestrone stimulation |
| Frequency | Common (about 55%) | Less common (about 45%) |
| Precursor lesion | Rarely, but if present: atypical endometrial hyperplasia | Presumed to be less uncommon: endometrial intraepithelial carcinoma/endometrial glandular dysplasia (‘p53 signatures’) |
| Histological type | Endometrioid carcinoma G1 (55%), mucinous carcinoma G1 | Serous papillary carcinoma (10%), clear cell carcinoma (5%), endometrioid carcinoma G2/G3 (20%), non-endometrioid carcinoma (10%) |
| Differentiation | G1 | G2–G3 |
| Receptor state | ER rich, PR rich | ER rich or ER poor, PR rich or PR poor |
| Myometrial invasion | Nil to inner 1/3 | Inner 1/3 to 3/3 |
| Lymphatic invasion | Less common | Common |
| Stage | I | I–IV |
| Prognosis | Almost excellent | Poor |
ER, oestrogen rceptor; PR, progesterone receptor.