Features favouring metastasis in ovarian mucinous tumours
| Feature | Comment |
| Bilateral ovarian involvement | This may not result in bilateral ovarian enlargement, thereby appearing unilateral (eg in signet ring carcinoma) |
| Maximum diameter <10 cm | About 15% tumours will not be correctly assigned on size and laterality criteria; cut-off points of 12 cm and 13 cm have been published, offering marginally better prediction; it has also been suggested that unilateral tumours 10–15 cm should be considered indeterminate |
| Extensive intra-abdominal spread | An alternative primary site may not be found in all such cases; rare true disseminated ovarian mucinous primaries have been reported |
| Multinodular growth pattern with intervening normal parenchyma | |
| Surface involvement | |
| Hilar involvement | |
| Infiltrative pattern of small glands with desmoplastic reaction, single cell infiltration | |
| Extensive vascular invasion | |
| Extensive necrosis | Torsion should be excluded |
| Patterns almost exclusive to metastasis: | Rare exceptions may occur, particularly in the presence of teratoma |
| Signet ring carcinoma | |
| Pseudomyxoma peritonei (ovarii) | |
| Colloid carcinoma | |
| Resemblance of tumour to known primary | ‘Maturation’ in metastasis may cause metastasis to appear dissimilar |