The sea anemone sign is a unique (but not wholly exclusive) appearance seen in ovarian serous surface papillary borderline tumors (SSPBT). It refers to its surface stroma frequently branches into exophytic papillary stalks, macroscopically 1.
Radiographic features
On cross-sectional imaging, particularly MRI, SSPBTs form frondlike excrescences that mimic the appearance of a sea anemone 1,2.
Early preoperative diagnosis with cross-sectional imaging can be vital because these tumors are less aggressive and tend to carry a better prognosis than other ovarian tumors.
These tumors were usually seen in younger women of childbearing age who can benefit from fertility-sparing surgery 2.