Dermoid cysts of the ovary with malignant transformation: MR appearance

OBJECTIVE. This study presents the MR appearances of five women with a total of six proven dermoid cysts of the ovary with malignant transformation. To our knowledge, the MR findings of this entity have not been reported. CONCLUSION. The lesions appeared to be fat-containing tumors with a solid component (4/6) that extended transmurally (4/6) and extensively invaded neighboring pelvic organs (3/6). The supervening malignancy was squamous cell carcinoma in four tumors, melanoma in one, and transitional cell carcinoma in one. The mode of spread differed from that of common ovarian tumors in that it included transmural extension and local invasion, reflecting squamous cell carcinoma.