Features favouring primary ovarian origin of mucinous tumours
| Feature | Comment |
| Unilateral | Bilateral metastatic tumours may not cause symmetrical or even comparable ovarian enlargement |
| Maximum tumour diameter >12 cm | Cut-off points of 10 and 13 cm have been published; it has also been suggested that tumours 10–15 cm should be considered indeterminate |
| Smooth outer surface | |
| Associated benign, borderline and malignant appearing areas | Maturation of ovarian metastases may result in a deceptively similar gradation of features |
| Complex papillary architecture | |
| Association with other background changes: | |
| Endometriosis (seromucinous tumours) | |
| Brenner tumour | |
| Mature cystic teratoma | |
| Sertoli–Leydig cell tumour | |
| Adenofibroma |