Table 1

Features favouring metastasis in ovarian mucinous tumours

Bilateral ovarian involvementThis may not result in bilateral ovarian enlargement, thereby appearing unilateral (eg in signet ring carcinoma)
Maximum diameter <10 cmAbout 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 spreadAn 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 necrosisTorsion 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