Proposed Risk Stratification and Patterns of Radioactive Iodine Therapy in Malignant Struma Ovarii.

Introduction: Malignant struma ovarii (MSO) is a rare thyroid cancer arising within an ovarian teratoma. While surgical excision of the primary tumor is widely accepted as standard of care, recommendations for adjuvant treatment of MSO-whether or not to administer radioactive iodine (RAI)-are based largely on case reports and remain debated. In this study, we aimed to propose a risk stratification and analyze RAI utilization patterns in MSO cases. Methods: The National Cancer Database (NCDB) was queried for patients with MSO between 2004 and 2016. Demographic, oncological, and clinicopathologic data were compared between groups using Fisher's exact test. Kaplan-Meier curves were used to estimate overall survival (OS), and variables associated with OS were assessed via univariate Cox regression. We adapted the 2015 American Thyroid Association risk guidelines for MSO patients. We stratified patients into low-, intermediate-, and high-risk groups using metastasis, extraovarian extension, lymphovascular invasion, lymph node status, surgical margins, tumor size, and grade. Risk stratification, demographic, oncological, and clinicopathologic data were compared between the groups receiving and not receiving RAI therapy. We then queried the Surveillance, Epidemiology, and End Results (SEER) 18 registry for patients with MSO between 2000 and 2018 to confirm our risk stratification analysis. Results: In the NCDB analysis, a total of 158 patients were identified, and 19 received RAI. RAI therapy was associated with distant metastasis (p = 0.005) and lymph node status (p = 0.012). Twenty-one NCDB patients were stratified as high risk, and 30% of high-risk patients received RAI. High-risk stratification was associated with decreased OS via univariate Cox regression (hazard ratio = 4.0 [95% confidence interval 1.11-14.26], p = 0.034). In our subsequent analysis using the SEER registry, there were 95 MSO patients, and 18 received RAI. Again, the majority of high-risk patients did not receive RAI, with only 41% of high-risk patients receiving RAI. Conclusions: MSO is a rare malignancy with apparently variable and inconsistent patterns of postoperative RAI administration. The risk stratification described here provides a framework to identify patients potentially at risk for mortality, and utilization of RAI in this group should be studied further.

Complete Remission After Single Radioiodine Therapy in Malignant Struma Ovarii With Bone and Lymph Node Metastases.

A 67-year-old woman presented with malignant struma ovarii after radical bilateral salpingo-oophorectomy. The surgery revealed a 4.4 cm papillary thyroid carcinoma (follicular variant) within a right-sided ovarian teratoma. I sodium iodide positron emission tomography / computed tomography and cervical ultrasound showed 2 slightly hyperfunctional thyroid nodules and several metastases, including bone metastases with intense iodine uptake. Thyroidectomy was necessary in preparation for radioiodine therapy and proofed the thyroid nodules to be benign. Complete remission was achieved by single radioiodine therapy (30 months of follow-up).

Malignant struma ovarii harboring a unique NRAS mutation: case report and review of the literature.

Struma ovarii (SO), a rare tumor containing at least 50% of thyroid tissue, represents approximately 5% of all ovarian teratomas; its malignant transformation rate is reported to occur in up to 10% of cases and metastases occur in about 5-6% of them. We describe a 36-year old woman who underwent laparoscopic left annessectomy two years earlier because of an ovarian cyst. Follow-up imaging revealed a right adnexal mass, ascitis and peritoneal nodes that were diagnosed as comprising a malignant SO with peritoneal secondary localizations at histopathology performed after intervention. Restaging with 18F-FDG-PET/CT scan, abdominal CT and ultrasonography showed abnormalities in the perihepatic region and presacral space and left hypochondrium localizations. The patient underwent thyroidectomy, hepatic nodulectomy and cytoreductive peritonectomy: histopathological examination did not show any malignant disease in the thyroid and confirmed the presence of peritoneal localizations due to malignant SO; molecular analysis detected NRAS Q61K mutation in exon 3, whereas no mutations were identified on the BRAF gene. The patient underwent radioiodine treatment: serum Tg was decreased at first follow-up after three months of 131I-therapy. We believe that our case raises some interesting considerations. First, pathologists should be aware of this entity and should check for the presence of point mutations suggesting an aggressive disease behavior, which could be beneficial for an optimal therapeutic approach. Second, although most of the knowledge in this field comes from case reports, efforts should be made to standardize the management of patients affected by malignant SO, including use of practice guidelines.

The lack of consensus in management of malignant struma ovarii.

Struma ovarii is a rare variant of teratoma characterized by the presence of thyroid tissue in more than 50%. Malignant transformation is rare (less than 5%) and the criteria to classify this condition have changed over time. Nowadays it must fulfill the histological categories of differentiated thyroid carcinoma. Its treatment is controversial and there is no unanimous management. We present three cases of women with malignant struma ovarii, diagnosed by the surgical specimen.

Malignant struma ovarii: the west of Scotland experience and review of literature with focus on postoperative management.

INTRODUCTION: Malignant struma ovarii is an extremely rare ovarian tumour containing malignant thyroid carcinoma within differentiated thyroid tissue, as the predominant tissue type. Surgery for suspected ovarian tumour and incidental pathological diagnosis is the most common presentation. Evidence supporting any particular approach to the clinical management of this condition is limited, mainly consisting of case reports, small series or pathological case series. There is no randomised evidence for postoperative management in view of the rarity of this condition. The opinion is divided between conservative management versus total thyroidectomy and radio-iodine ablation. METHODS: We carried out a retrospective review of our series with focus on postoperative management of this rare condition. A review of existing literature was also carried out. RESULTS: Six patients with a median age of 52 years presented with various symptoms of abdominal pain, pressure or menstrual problems. After the initial gynaecological resection and specialised pathology review, they were subsequently treated with total thyroidectomy and administration of radioactive iodine. All of these six patients are in remission at a median follow up of 60 months. CONCLUSION: We favour aggressive postoperative management with total thyroidectomy and radioactive iodine, and long-term follow up of these patients.

Metastatic struma ovarii treated with total thyroidectomy and radioiodine ablation.

OBJECTIVE: To present a rare case of metastatic struma ovarii, review the related literature, and discuss the management. METHODS: A case report of a patient with metastatic struma ovarii is presented. The treatment plan, postoperative care, and follow-up are discussed. We conducted a MEDLINE search of the English-language literature seeking additional cases of metastatic struma ovarii. In addition to the current case, the previous 40 cases of metastatic struma ovarii were reviewed and analyzed. RESULTS: The mean age of the patients at presentation was 43 years. All patients underwent resection of the primary tumor. The most common sites of involvement for struma ovarii metastatic disease have been the peritoneum, mesentery, and omentum. After primary tumor resection, a wide range of additional treatments have been used, including chemotherapy, resection of metastatic disease, external beam radiation therapy, and radioiodine ablation. CONCLUSION: In cases of metastatic struma ovarii, we recommend total thyroidectomy in conjunction with radioiodine scanning and radioiodine ablation. Thyroglobulin levels should be followed as a tumor marker, and diagnostic radioiodine scans should be performed to screen for residual or recurrent disease. Although this treatment strategy is well established for thyroid cancer, long-term outcomes of this treatment for struma ovarii are still unknown.

A case of metastatic struma ovarii treated with 131I therapy: focus on preservation of fertility and selected review of the literature.

Struma ovarii is a rare monodermal ovarian teratoma composed predominantly of mature thyroid tissue. We describe herein the case of a 22-year-old woman who underwent a right salpingo-oophorectomy for struma ovarii at the age of 12 years, who was admitted 8 years later with signs and symptoms of a left pelvic tumor. Laparoscopy detected a left ovarian endometriotic cyst and multiple nodules on the pelvic peritoneum, right lateral abdominal wall, diaphragm, vesical plica and liver. The diagnosis was abdominal and pelvic widespread dissemination of recurrent struma ovarii, with features consistent with the follicular variant of papillary thyroid carcinoma. The patient was treated with a combination of conservative surgery and two 131I administrations (cumulative activity of 350 mCi after dosimetric evaluation). Because of the high degree of hormonogenesis shown by the metastases, the first administration was performed following use of recombinant human (rh) thyroid-stimulating hormone (TSH) to reach adequate TSH levels. To avoid the 'stunning effect' and to obtain high-quality scintigraphy, a whole-body scan was performed with 123I after rh-TSH and before the 131I therapy. We also discuss the potential role and the possible benefit of using gonadotropin-releasing hormone analogs and ovarian tissue cryopreservation to preserve fertility in women treated with 131I for pelvic metastases from malignant struma ovarii.

Metastatic struma ovarii: late presentation, unusual features and multiple radioactive iodine treatments.

Metastatic malignant struma ovarii is rare and there is a lack of agreement on the criteria of diagnosis and the lines of management. Here we describe a patient with struma ovarii that was initially diagnosed as benign and presented 10 years later with distant metastases. At this time, a pathological review of the initial lesion found that it contained invasive well-differentiated follicular carcinoma. The case was associated with a number of unusual features and challenging management issues, such as a delayed diagnosis of recurrence, functioning metastases with treatment consequences, tumour lysis-induced thyrotoxicosis and cerebrospinal fluid rhinorrhea. The diagnosis and management of struma ovarii should be led by an expert multidisciplinary team. Radioactive iodine should be considered in the management of metastatic disease.

Malignant struma ovarii: a case report and analysis of cases reported in the literature with focus on survival and I131 therapy.

BACKGROUND: Malignant struma ovarii is a rare type of germ cell tumor that is most often diagnosed postoperatively. The natural history and optimal treatment regimen for the disease are essentially unknown due to the small numbers of published cases. CASE: A 32-year-old woman presented with pelvic pain and an ovarian mass that was ultimately treated by total abdominal hysterectomy/bilateral salpingo-oophorectomy. Postoperatively, she was diagnosed with a malignant struma ovarii. The patient was subsequently treated with thyroidectomy and I(131) ablation and is currently disease free. A Medline literature search was performed and clinical data from 23 additional cases were compiled. CONCLUSION: In this review of 24 cases, 16 patients were followed conservatively postoperatively while 8 received varied additional therapy (4 with I(131)). There were 8 recurrences and all occurred in the conservatively managed patients. I(131) for recurrent disease provided an initial complete response in 7 women. Treatment with thyroidectomy and I(131) should be considered in the first line of management for malignant struma ovarii.

Recombinant human thyrotropin for the diagnosis and treatment of a highly functional metastatic struma ovarii.

The optimal treatment of metastatic thyroid cancer that produces high amounts of thyroid hormone has not been well defined. A 46-yr-old woman presented with a follicular thyroid carcinoma arising from a struma ovarii with hepatic metastases. After the removal of both the struma and the thyroid gland, the liver metastases showed evidence of a high degree of hormonogenesis. Brain, chest, abdomen, and bone imaging was negative for additional metastases. Because iodine uptake by most thyroid carcinomas is quite low in the absence of high levels of ambient TSH, we used recombinant human TSH (rhTSH) (Thyrogen) to achieve a concentration of 131I activity in the tumor high enough for a significant cytotoxic effect. After rhTSH administration (0.9 mg im daily for 2 consecutive days), a 131I diagnostic whole body scan confirmed the existence of 17 discrete hepatic foci of 131I uptake. To calculate the amount of 131I that would deliver an absorbed radiation dose that would be optimally cytotoxic to the metastases (>8000 rad/lesion) and not to the normal liver, we performed lesion dosimetry. Analysis of dosimetric data showed that 15 of 17 lesions would receive an adequate radiation dose following the administration of 65 mCi of 131I. Additionally, we performed whole body dosimetry to assure that this dose would not cause bone marrow toxicity. The patient was reevaluated 6 months after therapy; the liver metastases showed significant, but partial, response. In conclusion, we used the combination of rhTSH with lesional and whole body dosimetry for the treatment of highly functional metastases from follicular thyroid carcinoma arising within a struma ovarii. This strategy can be applied to determine a safe and effective dose of 131I for the treatment of any thyroid cancer metastases that produce enough TH to preclude stimulation of endogenous pituitary TSH secretion.

Radiotherapy with iodine-131 in recurrent malignant struma ovarii.

Malignant struma ovarii is a very rare disease and, therefore, there is neither common agreement on treatment regimens nor sufficient follow-up experience. We present a case of a 49-year-old woman with malignant struma ovarii of the follicular type, who received ablative radioiodine treatment after thyroidectomy and surgical removal of the primary tumour. During follow-up examinations an increasing thyroglobulin level was found, caused by a tumour relapse with suspected urinary bladder infiltration on CT and proven uptake of radioiodine on whole-body scanning with iodine-131. After administration of 6GBq 131I, complete tumour regression was achieved with no evidence of a new relapse during a 30-month follow-up period. Correspondingly, repeated thyroglobulin measurements were all negative. This case demonstrates the benefit of combined surgical and radioiodine treatment of malignant struma ovarii for both monitoring and therapy of relapse or metastases; thus, the same therapeutic regimen as is employed in primary differentiated thyroid carcinoma may be recommended.

[Struma ovarii maligna]. / Struma ovarii maligna.

Benign and malignant struma ovarii are very rare ovarian teratomas. Specific therapy guidelines should be established. A case of a malignant struma ovarii is presented and results of therapy discussed.

Malignant struma ovarii treated by ovariectomy, thyroidectomy, and 131I administration.

A 36-year-old woman presented with an intraperitoneally disseminated malignant struma ovarii, diagnosed by histopathology and 131I scintigraphy. The serum thyroglobulin level was elevated, and immunoperoxidase staining for thyroglobulin was positive for disease both in the tumor cells lining the follicles and in the colloid. The patient was treated successfully by a bilateral ovariectomy followed by a total thyroidectomy and administration of radioactive iodine. The clinical behavior and the presence of thyroglobulin in both serum and tumor tissue demonstrate the similarity between neoplastic thyroid tissue in the ovary and in the thyroid gland.