Malignant Struma Ovarii: An Unusual Presentation

Abstract

Malignant struma ovarii is a rare disease; only a few cases are well documented in the literature. Thus, the overall prognosis and modalities of treatment are still somewhat controversial. In this article, the authors report a case of malignant struma ovarii discovered 4 years after ovariectomy after metastasis to the lungs and bones. Review of the pathology of the ovarian struma did not reveal the classic criteria of malignancy, there were, however, many features considered to be atypical and thus suspicious. The patient was treated by total thyroidectomy followed by repetitive doses of 131I. However, because of difficulties in increasing the level of endogenous thyrotropin (TSH) because of functional thyroid metastases in such an advanced disease, recombinant human thyrotropin (rhTSH; Thyrogen, thyrotropin alpha, Genzyme Corporation, Cambridge, MA) was used before administration of radioiodine. With this therapeutic protocol, the patient is still clinically stable 2 years after diagnosis.

Usefulness of 131I-SPECT/CT and 18F-FDG PET/CT in Evaluating Successful 131I and Retinoic Acid Combined Therapy in a Patient with Metastatic Struma Ovarii

“…Malignant struma ovarii is a very rare disease [9][10][11][12]. The clinical course of extraovarian spread and the gold standard therapy have not been fully established.…”

Two Cases of Malignant Struma Ovarii with Metastasis to Pelvic Bone

“…Checrallah et al [7] described a case of malignant struma ovarii that metastasized to the lungs and pelvic bones. McGill et al [6] presented a case of metastatic struma ovarii to the right upper extremity, mediastinum, and bilateral hips.…”

“…Wynne et al [8] reported a case of metastatic struma ovarii to the ischium. Of the bone metastasis previously reported in the English literature, the specific bone locations varied; 4 cases occurred in the spine [4,9,10,11], 2 in skull [12,13], 4 in pelvic bone [6,7,8,10], and one case did not provide the exact location of the bone metastasis [14]. It is interesting that both of our patients had metastases to the left pelvic bone, and this report together with those in the literature makes pelvic bone the most favored site for bony metastasis.…”

“…Other sites, in decreasing order of frequency, include the liver, contralateral ovary, bone, and lung [6]. Bone is not a common site for metastasis, and there are only about 10 cases in the English literature which have reported bony metastasis [4,6,7,8,9,10,11,12,13,14]. …”

“…For patients with advanced disease or recurrences, adjuvant therapy includes chemotherapy; external beam radiation has been used [16]. As with thyroid cancer, recombinant human TSH has been used to increase the effectiveness of I-131 [7,15,18], and thyroglobulin has been used to monitor for recurrence [1]. The question still remains, however, as to which of these methods is most effective in achieving higher survival and remission rate in patients with malignant struma ovarii.…”