Malignant transformation of an endometriotic cyst: MDCT and MR findings.

Malignant transformation is a rare complication of endometriosis. MR criteria for diagnosis include the presence of soft-tissue components, enhancement after contrast material administration in an endometriotic cyst. We present the multidetector CT and MR imaging findings in a case of an incidentally found endometrioid adenocarcinoma in a left-sided ovarian endometrioma, occurring in a 30-year old woman. MR imaging enabled the correct preoperative characterization of the lesion, by depicting a soft-tissue element, with strong and early enhancement after gadolinium administration. The same area had high signal intensity on diffusion-weighted images and low apparent diffusion coefficient values due to restricted diffusion, findings also strongly suggestive of malignancy.