Dermoid cysts of the ovary with malignant transformation: MR appearance

Staging ovarian cancer: role of imaging

Ovarian cancer is relatively common, and often presents at an advanced stage with widespread intraperitoneal metastases. The constellation of complex pelvic masses, ascites, omental cake, and other peritoneal implants is virtually diagnostic. All patients are potential surgical candidates, since suspected early stage disease is treated by a comprehensive staging laparotomy including total abdominal hysterectomy, bilateral salpingo-oophorectomy, and omentectomy. Operable advanced disease is treated by surgical debulking and adjuvant combination chemotherapy. The role of imaging is to detect and characterize adnexal masses as likely malignant, recognize unusual findings that may suggest atypical pathology, demonstrate metastases in order to prevent under-staging, and detect specific sites of disease that may be unresectable. These aims are directly related to clinical management; characterization of an adnexal mass as malignant guides appropriate surgical referral, recognition of atypical pathology such as malignant granulosa cell tumor in a young woman may be an indication for fertility-preserving surgery. Demonstration of metastatic site-assists surgical planning, and detection of unresectable disease may be an indication for neoadjuvant (ie, preoperative) chemotherapy with interval debulking rather than primary debulking with adjuvan (postoperative) chemotherapy.

Magnetic resonance imaging of the ovary

Magnetic resonance imaging (MRI) of the pelvis can characterize a wide variety of ovarian lesions. We discuss MRI strategies for identification and characterization of ovarian neoplasms and correlate MRI findings with lesion gross pathological and histopathological structure.

Ovarian teratomas: tumor types and imaging characteristics

Ovarian teratomas include mature cystic teratomas (dermoid cysts), immature teratomas, and monodermal teratomas (eg, struma ovarii, carcinoid tumors, neural tumors). Most mature cystic teratomas can be diagnosed at ultrasonography (US) but may have a variety of appearances, characterized by echogenic sebaceous material and calcification. At computed tomography (CT), fat attenuation within a cyst is diagnostic. At magnetic resonance (MR) imaging, the sebaceous component is specifically identified with fat-saturation techniques. The US appearances of immature teratoma are nonspecific, although the tumors are typically heterogeneous, partially solid lesions, usually with scattered calcifications. At CT and MR imaging, immature teratomas characteristically have a large, irregular solid component containing coarse calcifications. Small foci of fat help identify these tumors. The US features of struma ovarii are also nonspecific, but a heterogeneous, predominantly solid mass may be seen. On T1- and T2-weighted images, the cystic spaces demonstrate both high and low signal intensity. Familiarity with the US, CT, and MR imaging features of ovarian teratomas can aid in differentiation and diagnosis.