The detection of struma ovarii in two patients by radioimmunoscintigraphy

Malignant struma ovarii mimic clear cell carcinoma

INTRODUCTION

Struma ovarii are quite unusual lesions that represent less than 3% of all teratomas and its malignant transformation is very uncommon. The clinical manifestations are characteristic of pelvic tumor and the hormonal metabolism is not usually modified. Radiography, employing ultrasound procedures, is the most commonly used pre-surgical detection method but only histological examination makes the diagnosis. The malignance recognition by pathological study not always is easy; in this sense, it requires an exhaustive sampling of the lesion, being specially carefully in some aspects related with malignant transformation such as extending beyond the capsula and involving peripheral tissues. A thyroidal differentiation must be confirmed by immunohistochemical study and other local processes with similar histology should be ruled out. Given the exceptional character of malignant forms, there does not appear to be unanimous agreement on a standard therapy with a somewhat uncertain prognosis.

CASE REPORT

We show a case of a 22-year-old patient with an ovarian tumor that was discovered by ultrasound examination and surgically removed. The histologic study revealed struma ovarii with malignant transformation towards follicular carcinoma and unlike previously published cases, had a prevalence of clear cells. The patient was submitted to a second surgical staging intervention, with conservative surgery and follow-up controls being considered given that was a young woman with a desire to have children. Laparoscopy was employed as the best method capable to facilitate shorter convalescence.

OUTCOME

Clinical and analytical controls, measuring thyroglobulin levels, has been satisfactory up to the present.

Preoperative diagnosis of ovarian carcinoma with a novel monoclonal antibody

OBJECTIVE

This study was undertaken to determine whether preoperative radioimmunoscintigraphy of complex ovarian masses with technetium Tc 99m MAb-170 (Tru-Scint AD; Biomira Inc, Edmonton, Alberta, Canada), a murine whole immunoglobulin G monoclonal antibody that has been found to have panadenocarcinoma affinity, would predict surgical findings.

STUDY DESIGN

The age range of studied patients was 42 to 83 years (mean, 60.3 years). Planar computed tomographic imaging and single-photon emission computed tomographic imaging were performed at 15 minutes, 6 to 8 hours, and 18 to 24 hours after injection of 1000 MBq technetium Tc 99m MAb-170. Laparotomy was performed within 10 days.

RESULTS

Eighteen patients had borderline or invasive ovarian cancers verified by histologic examination. All primary malignancies or deposits (including intrahepatic deposits) yielded positive results on radioimmunoscintigraphic imaging. Radioimmunoscintigraphy was able to identify serosal deposits not seen on computed tomographic or ultrasonographic scans. False-positive localization of the antibody was noted in 6 of the 9 patients with benign pathologic processes.

CONCLUSION

It is possible to detect with technetium Tc 99m MAb-170 all patients who have cancer (including sites not seen on computed tomographic or ultrasonographic scan); however, the low specificity (33%) means that patients still require surgical verification of disease.

MR findings of struma ovarii

This study was performed to characterize MR findings of struma ovarii. In 10 patients, T1- and fast spin echo T2-weighted MR images were obtained in the axial, coronal, and sagittal planes using 1.5 T MR units, and they were retrospectively evaluated for the site, size, components, signal intensity, and contrast enhancement.MR images showed a unilateral complex mass with a multilobulated surface and thickened septa, corresponding pathologically to thyroid follicles and the stroma. Cystic portions had variable signal intensities on T1- and T2-weighted images. The contents of cystic components showing low signal intensities both on T1- and T2-weighted images were viscid gelatinous materials (n=4). Solid portions were relatively well-enhanced. In conclusion, struma ovarii has some characteristic MR appearance of a multilobulated complex mass with thickened septa, multiple cysts of variable signal intensities, and enhancing solid components.