Which of the following is not true regarding a krukenberg tumour

Krukenberg tumor is diagnosed only if it conforms to the following pattern ; Almost bilateral Smooth surfaces Freely mobile in pelvis It retains the shape of normal ovary. The tumors are secondary growth in the ovary and most often arise from a primary carcinoma of the stomach(70%). Histologically, the tumor has a cellular or myxomatous stroma amongst which are scattered large signet ring cells. Ref: Shaw Gynecology 17 e pg 464.