CT and MR imaging of ovarian tumors with emphasis on differential diagnosis

Borderline tumors of the ovary: CT and MRI features and tumor markers in differentiation from stage I disease

OBJECTIVE

We sought to describe MDCT and MRI features and tumor marker levels that differentiate borderline ovarian tumors from stage I ovarian tumors.

CONCLUSION

Borderline ovarian tumors are complex masses with imaging features similar to stage I tumors. The thickness of septations and the size of solid components are significantly larger in stage I tumors, and these features may be helpful for predicting likelihood of invasive tumors. However, neither feature allows confident differentiation of borderline tumors from stage I disease.

Preoperative sonographic features of borderline ovarian tumors

OBJECTIVE

To determine the sonographic findings that distinguish borderline ovarian tumors (BOT) from both benign and invasive malignant tumors, thus allowing conservative treatment and laparoscopic management of these tumors.

METHODS

We reviewed retrospectively transvaginal sonograms of 33 women who, when evaluated further by surgery and histology, were found to have BOT. Twenty-three were premenopausal and 10 were postmenopausal (mean age +/- SD, 45.8 +/- 15.7 years). For each mass, size and morphological features and power Doppler characteristics were evaluated. We compared these findings with those of 337 patients with benign ovarian tumors and those of 82 patients with invasive malignant ovarian tumors. Patients with dermoid cysts were not included in the study.

RESULTS

Of the 33 BOT, 15 were mucinous and 18 were serous cystadenomas. The presence of papillae, defined as a small number of solid tissue projections, 1-15 mm in height and 1-10 mm in width (base) and length (base), into the cyst cavity from the cyst wall, was significantly more frequent in BOT (48%) than it was in benign (4%) and invasive (4%) malignant tumors. Intracystic solid tissue (> 15 mm in height or > 10 mm in width or length) was observed in 48% of invasive malignant masses but in only 18% of BOT and in 7% of benign tumors (P < 0.001). No sonographically unilocular, hypoechoic, smooth-walled adnexal cysts were invasively malignant but three unilocular cysts with a diameter of > 6 cm were serous BOT. Although close attention was paid to the cyst wall at ultrasound examination we did not observe in these three cysts the very small papillae which were found at histological analysis.

CONCLUSIONS

The most frequent diagnostic feature on imaging BOT is the presence of papillae within the cyst. However, neither papillae nor other sonographic features constituted highly sensitive sonographic markers of BOT.

Comparison of true FISP with turbo SE in ovarian imaging

PURPOSE

To compare the signal pattern of True FISP (true fast imaging with steady state precession) with that of T2-weighted TSE (turbo spin echo) sequencing in several ovarian pathologies and to clarify the pathologies that may be misdiagnosed when True FISP is used as a fast T2-weighted MR (magnetic resonance) imaging technique.

METHODS

A total of 56 patients with 58 ovarian lesions were prospectively studied. The histopathological diagnoses were surgically confirmed in all patients. All MR images were acquired with a 1.5T MR scanner. After routine MR examination (T2-weighted sagittal imaging with a turbo spin echo sequence and T1 and T2 transverse imaging with a spin echo and turbo spin echo sequence, respectively), True FISP was performed in the sagittal plane with a fat-saturation technique. The acquisition times for the True FISP and TSE techniques were 27 s and 4 min, 42 s, respectively. Three radiologists interpreted all images according to three grading scores and with particular reference to the difference in signal pattern between the two sequences (1=similar signal patterns in the ovarian lesions in both True FISP and TSE images; 2=partially different signal patterns in both True FISP and TSE images; and 3=conflicting signal patterns in both True FISP and TSE images).

RESULTS

Those assigned a score of "1" included 30 patients with 30 ovarian lesions (12 malignant lesions and 18 benign lesions); those assigned a score of "2" included 10 patients with 10 lesions (two malignant and eight benign); and those assigned a score of "3" included 16 patients with 18 ovarian lesions (two malignant and 16 benign). With the influence of the fat-suppression technique excluded, eight ovarian lesions showed conflicting signal patterns between the two sequences and high signal intensity of hemorrhaging in the corresponding lesion in T1-weighted images. Lesions of both high and low signal intensity in TSE images appeared as lesions of high signal intensity in True FISP images. About 14% (8/56 lesions) of the True FISP and TSE signal patterns in ovarian pathology were conflicting in this study.

CONCLUSION

The results indicate that the True FISP technique cannot replace the T2-weighted TSE technique in the evaluation of ovarian pathology. T1-weighted images with or without fat suppression are required for the evaluation of ovarian lesions with FISP images.

Malignant transformation of an ovarian mature cystic teratoma: computed tomography findings

INTRODUCTION

The malignant transformation of an ovarian mature cystic teratoma is rare. We presented such a case of a 46-year-old woman with characteristic computed tomography (CT) findings.

CASE REPORT

The patient had suffered from fullness and tenderness of the lower abdomen for one year. A high serum CA-125 level was noted. Computed tomography images showed a left adnexal mass with fat, calcification and soft tissue components, and areas of invasion through the teratoma wall.

OUTCOME

The histologic diagnosis was compatible with a squamous cell carcinoma arising from a mature cystic teratoma of the ovary.

Primary Peritoneal Clear Cell Carcinoma

The computed tomography (CT) and magnetic resonance imaging findings of primary peritoneal clear cell carcinoma in a 53-year-old woman are reported. A CT scan showed a complex cystic mass with solid components that involved the right upper quadrant and displaced the liver and the right kidney. Magnetic resonance imaging revealed a multicystic mass with hemorrhage and heterogeneous solid protrusions. The diagnosis of primary peritoneal clear cell carcinoma was made by histopathologic study of the surgical specimen.

From the archives of the AFIP: radiologic staging of ovarian carcinoma with pathologic correlation

Ovarian cancer is the deadliest gynecologic malignancy, with approximately 70% of patients having peritoneal involvement at the time of diagnosis. It spreads predominantly by direct invasion and intraperitoneal dissemination. The staging system is surgically based, with stage I disease being limited to one or both ovaries. In stage II disease, there is extraovarian spread of tumor, but it does not extend beyond the pelvis. Stages III and IV disease are considered advanced, with stage III ovarian cancer including diffuse peritoneal disease involving the upper abdomen and stage IV disease having distant metastases including hepatic lesions. Common sites of intraperitoneal seeding include the omentum, paracolic gutters, liver capsule, and diaphragm. Thickening, nodularity, and enhancement are all signs of peritoneal involvement. Although computed tomography is the most common imaging modality used to stage ovarian cancer, magnetic resonance imaging has been shown to be equally accurate. Currently, however, no imaging modality allows microscopic spread of disease to be ruled out, and a full staging laparotomy is always required. Early ovarian cancer is treated with comprehensive staging laparotomy, whereas advanced but operable disease is treated with primary cytoreductive surgery (debulking) followed by adjuvant chemotherapy. Patients with unresectable disease may benefit from neoadjuvant (preoperative) chemotherapy before debulking.

Sclerosing stromal tumor of the ovary: MR-pathologic correlation in three cases

Sclerosing stromal tumor (SST) of the ovary is a very rare sex cord stromal tumor occurring in a younger age group than other types of stromal tumors and most commonly accompanied by menstrual irregularity. Several unique histologic features including pseudolobulation, sclerosis and prominent vascularity are clearly reflected at ultrasonography and MRI. We report the ultrasonographic and MR features of three cases of histologically confirmed SSTs, and relate them to the pathological findings.