Optimal surgical management of well-differentiated thyroid cancer arising in struma ovarii: a series of 4 patients and a review of 53 reported cases

Personalized approach to malignant struma ovarii: Insights from a web-based machine learning tool

OBJECTIVES

Malignant struma ovarii (MSO) is a rare ovarian tumor characterized by mature thyroid tissue. The diverse symptoms and uncommon nature of MSO can create difficulties in its diagnosis and treatment. This study aimed to analyze data and use machine learning methods to understand the prognostic factors and potential management strategies for MSO.

METHODS

In this retrospective cohort, the Surveillance, Epidemiology, and End Results (SEER) database provided the data used for this study's analysis. To identify the prognostic variables, we conducted Cox regression analysis and constructed prognostic models using five machine learning algorithms to predict the 5-year survival. A validation method incorporating the area under the curve of the receiver operating characteristic curve was used to validate the accuracy and reliability of the machine learning models. We also investigated the role of multiple therapeutic options using the Kaplan-Meier survival analysis.

RESULTS

The study population comprised 329 patients. Multivariate Cox regression analysis revealed that older age, unmarried status, chemotherapy, and the total number of tumors in patients were poor prognostic factors. Machine learning models revealed that the multilayer perceptron accurately predicted outcomes, followed by the random forest classifier, gradient boosting classifier, K-nearest neighbors, and logistic regression models. The factors that contributed the most were age, marital status, and the total number of tumors in the patients.

CONCLUSION

The present study offers a comprehensive approach for the treatment and prognosis assessment of patients with MSO. The machine learning models we have developed serve as a practical, personalized tool to aid in clinical decision-making processes.

The Role of Radioiodine Therapy in Differentiated Thyroid Cancer Arising from Struma Ovarii: A Systematic Review

Background: Struma ovarii (SO) is an ovarian teratoma with the presence of ectopic thyroid tissue. Differentiated thyroid cancer (DTC) in SO is a rare finding. Management of DTC in SO is currently not clearly established. We performed a systematic review of the literature to assess the role of 131I radiometabolic therapy in the treatment of DTC in SO. Methods: a wide literature search in the Scopus, PubMed/MEDLINE, and Web of Science databases was made to find published articles regarding the treatment of patients with DTC and SO. The quality assessment of studies was performed by QUADAS-2 evaluation. Results: eleven studies were included in the systematic review. All of them were retrospective studies and/or case series, and two of them also included a review of the literature. Most of the studies describe cases of DTC in SO treated by total thyroidectomy (TT) and subsequent radioiodine (RAI) therapy, especially in patients with distant metastases and/or concomitant thyroid cancer. However, the majority of patients apparently did not require radiometabolic therapy. Conclusions: TT and subsequent RAI therapy is usually performed in metastatic disease, not recommended in patients with intraovarian disease without risk factors, and it appeared possible but not mandatory in patients with risk factors.

Recurrent malignant struma ovarii presenting as peritoneal carcinomatosis in the setting of an intact thyroid: A case report and review of the literature

Malignant struma ovarii is an exceedingly rare pathology with a paucity of established criteria regarding management and surveillance with recommendations largely based on case reports and retrospective data. Many authors have supported stratification of malignant struma ovarii into low vs high-risk disease with more conservative management reserved for those deemed low-risk. Here we present a unique case of recurrent metastatic malignant struma ovarii after surveillance was undertaken in the setting of initially low-risk disease.

Clinical Manifestations of Malignant Struma Ovarii: A Retrospective Case Series in a Tertiary Hospital in Korea

BACKGRUOUND

Malignant struma ovarii (MSO) is a very rare disease in which thyroid cancer originates from the ovary. Because it is rare for endocrinologists to encounter patients with MSO, endocrinologists may have a limited understanding of the disease. Therefore, we analyzed and introduced its incidence and clinical course in a tertiary hospital in Korea.

METHODS

We retrospectively investigated the clinical data of 170 patients who underwent surgery for struma ovarii at the Department of Obstetrics and Gynecology of Samsung Medical Center from 1994 to May 2023.

RESULTS

Among 170 patients with struma ovarii, 15 (8.8%) were diagnosed with MSO. The median age of patients with MSO was 48 years (range, 30 to 74), and the median tumor size was 3.3 cm (range, 0.5 to 11.0). Papillary thyroid carcinoma (46.7%) was the most common subtypes followed by follicular thyroid carcinoma (26.7%). All patients were diagnosed after surgery, with no predictions from preoperative imaging. The surgical extent of gynecological surgery was variable. Four patients (26.7%) underwent thyroidectomy for thyroid cancer, while one underwent total thyroidectomy and radioactive iodine therapy for MSO with peritoneal metastasis. Except for one patient who underwent hemithyroidectomy, thyroid stimulating hormone suppression therapy was performed in four patients. Only 53% of MSO patients were consulted by an endocrinologist. With a median follow-up period of 33 months (range, 4 to 156), 11 patients remained disease-free, one experienced progression with peritoneal seeding, and the remaining one was in treatment. There have been no recurrences or deaths due to MSO.

CONCLUSION

An endocrinologist should be involved in establishing a therapeutic plan for MSO, for which the overall prognosis is generally favorable.

A case report of malignant struma ovarii with papillary thyroid carcinoma

Key clinical message

Struma ovarii (SO), is a rare and specialized ovarian teratoma. The treatment is controversial depending on the risk of recurrence and metastasis. Here a SO with papillary thyroid carcinoma is reported and the approach is thoroughly discussed.

Abstract

Struma ovarii (SO) is a highly specialized ovarian teratoma primarily composed of thyroid tissue. Clinical features associated with SO include lower abdominal discomfort, unusual vaginal bleeding, ascites, and hyperthyroidism. While SO rarely transforms into malignancy, the optimal degree of treatment remains controversial due to the varying risks of recurrence and metastasis. In this report, we present the case of a 64-year-old woman experiencing abdominal pain and diagnosed with SO, accompanied by papillary thyroid carcinoma. We thoroughly discuss the evaluation and management of this rare condition.

Presentation and treatment of two cases of malignant struma ovarii

BACKGROUND

Malignant Struma Ovarii (MSO) is a rare type of germ cell tumour which is diagnosed postoperatively on surgical pathology specimens by the presence of differentiated thyroid cancer in mature cystic teratomas in the ovaries. Treatment and follow-up procedures are not clearly established due to the paucity of MSO cases. CASE 1: A 44-year-old multiparous female presented with an irregular period. Ultrasound showed a left ovarian lesion mostly a dermoid cyst, however, CT showed a 3.8 × 2.7 × 4 cm complex cystic lesion with thick septation and enhancing soft tissue component. Laparoscopic left salpingo-oophorectomy was performed and histopathology showed a follicular variant of papillary thyroid carcinoma arising in a mature cystic teratoma. Peritoneal cytology was positive for malignancy. A thyroid function test was normal before surgery. Total thyroidectomy was performed followed by radioactive (RAI) iodine therapy. Later, a total laparoscopic hysterectomy and right salpingo-oophorectomy were performed. There is no evidence of recurrent disease during the 26-months follow-up. CASE 2: A 46-year-old single female presented with left lower abdominal pain that had persisted for 2 months. Imaging revealed an 8 × 9 × 9.5 cm left ovarian mass. Laparoscopic left salpingo-oophorectomy was performed and histopathology showed mature cystic teratoma with small papillary thyroid cancer. CT showed no evidence of metastatic disease. Later, the patient had a total thyroidectomy followed by radioactive (RAI) iodine therapy. She was started on thyroxine and later had total abdominal hysterectomy and right salpingo-oophorectomy.

CONCLUSION

MSO is a very rare tumour. Preoperative diagnosis is very difficult because of the nonspecific symptoms and the lack of specific features in imaging studies. Also, there is no consensus on the optimal treatment of women with MSO. Our two cases add to the limited number of MSO cases.

Endocrine tumors of the female reproductive tract

Endocrine cells responsible for hormone secretion are found in virtually every organ system. The diverse neoplasms arising from endocrine cells in the female reproductive tract are not well recognized as a distinct component of endocrine oncology. Here, we integrate cellular origins with native anatomical residence to help classify neoplasms of this system. The neoplasms include steroidogenic tumors that arise usually in ovarian stroma, neuroendocrine neoplasms that can arise from normal neuroendocrine cells throughout the female reproductive tract or in ovarian germ cell tumors, and thyroid follicular cell proliferations that are exclusively a component of an ovarian teratoma and may be malignant. The neuroendocrine neoplasms run the full spectrum from indolent neuroendocrine tumors to aggressive poorly differentiated neuroendocrine carcinomas. While many of these lesions are identified as incidental findings in surgically resected tissues, others present with inappropriate hormone excess. An important consideration is the distinction of primary disease from metastatic malignancy. Genetic disorders including those caused by germline mutations of the FOXL2, GNAS, DICER1, STK11 and MEN1 genes can present with primary endocrine neoplasms of the female reproductive tract.

RET/PTC rearrangement in papillary thyroid carcinoma arising in malignant struma ovarii with abdominal wall metastasis and cervical thyroid gland: a case report and review of the literature

BACKGROUND

Struma ovarii refers to rare mature cystic teratomas containing at least 50% of thyroid tissue, and malignant transformation is known to be even rarer. The synchronous development of malignant struma ovarii and cervical thyroid carcinoma are also scarce and poorly understood due to limited data about molecular features. Here, we present the first report of RET/PTC 1 rearrangement in synchronous metastatic malignant struma ovarii to the abdominal wall and cervical thyroid cancer.

CASE PRESENTATION

We described a 47-year-old multigravida woman with bilateral adnexal and lower abdominal wall masses detected during the evaluation of abnormal uterine bleeding. The patient underwent a hysterectomy, bilateral salpingo-oophorectomy, and surgical removal of abdominal wall mass. Then, the pathological evaluation revealed papillary thyroid carcinoma (PTC) within struma ovarii and metastatic PTC in the abdominal wall fibro adipose tissue. Further, cervical thyroid gland physical examination and ultrasound illustrated a nodule within the left lobe. Subsequently, a total thyroidectomy was performed, and a histological examination revealed PTC. Furthermore, all affected tissue, i.e., struma ovarii, abdominal wall metastasis, and cervical thyroid gland tested for BRAF and RAS mutations and RET/PTC 1 rearrangement. RET/PTC 1 rearrangement was identified among all three different sites. Finally, after six years of follow-up, the patient had no evidence of recurrence or distant metastasis.

CONCLUSIONS

In light of these findings, malignant struma ovarii might yield a clue to cervical thyroid carcinoma, and the molecular analysis could provide valuable information for understanding the underlying mechanism, tumor clinicopathological behaviors, and prognosis.

Struma Ovarii with Papillary Thyroid Carcinoma and Metastasis to the Appendix: A Case Report and Literature Review

Struma ovarii is an infrequent type of teratoma arising from the ovary accounting for only 2% of all ovarian teratomas. These tumors have a benign biology with rare malignant transformation in about 3% of cases. The most common malignant transformation that arises from struma ovarii is papillary thyroid carcinoma. These neoplasms act in the same way as those arising from the thyroid gland, but due to the rarity of their occurrence there is still a debate over therapeutic options. We present a case of a 41-year-old Ethiopian Para IX woman presented with abdominal swelling for four years, accompanied by dull pain, satiety, and weight loss. Her vital signs were normal, and her abdominal examination revealed a large abdominopelvic mass. Her CA-125 was elevated, and her blood count, organ function tests, and serum electrolyte levels were normal. Abdominal ultrasound revealed a complex abdominopelvic mass with cystic and solid components, possibly ovarian teratoma. The patient underwent surgery, revealing a 14 by 10 cm right ovarian mass and a 3×3 cm appendiceal mass. Subsequently, total abdominal hysterectomy, bilateral salpingo-oophorectomy, total omentectomy, and appendectomy was done. Histopathologic evaluation revealed follicular proliferation of enlarged cells, with no papillary growth pattern. The case was diagnosed as malignant struma ovarii, a follicular variant of papillary thyroid carcinoma (FVPTC) with secondary deposits on the appendix. A complete thyroidectomy was done after the histopathology diagnosis. Malignant struma ovarii is rare making it challenging to treat since there are no established prognosticating histopathologic or clinical characteristics. The tumor size and metastasis determine the surgical treatment scope. Large-scale investigations are essential for prognostication and treatment options considering pathologic traits.

Incidence, clinical characteristics, and survival outcomes of ovarian strumal diseases: a retrospective cohort study

BACKGROUND

Struma ovarii (SO) is a rare tumor and may transform into ovarian strumal carcinoid (OSC) and/or malignant struma ovarii (MSO), but the incidence, clinical characteristics, and survival outcomes have not been well defined.

METHODS

We conducted a retrospective study of patients with ovarian strumal diseases treated in the our hospital between 1980 and 2022. Subgroup analyses of SO, OSC, and MSO were subsequently performed.

RESULTS

A total of 275 cases (2.14%) were identified in a cohort of 12,864 patients with ovarian teratomas, where SO, OSC, and MSO accounted for 83.3%, 12.0%, and 4.7% of cases, respectively. There were no significant differences in age, tumor sizes, elevated tumor markers, and ascites among the three subgroups. At initial treatment, all patients with SO or OSC had FIGO stage I disease except one SO patient presenting metastatic disease, ten patients had MSO confined to the ovary, whereas other three patients had metastatic diseases. Two patients with SO respectively relapsed at peritoneum and anterior mesorectum, while none of the OSC patients presented tumor recurrence or death despite different surgical procedures employed. The 5-year recurrence-free survival rate was 88.9%, and only one death occurred at 9.5 years after diagnosis in patients with MSO. Radioiodine therapy showed satisfactory therapeutic efficacy, but these patients showed poor responses to the chemotherapy.

CONCLUSION

2.14% of ovarian teratoma could be classified as SO, of which 12.0% and 4.7% of SO may transform into OSC and MSO, repsectively. The survival outcomes were excellent even after SO transformed into OSC or MSO.

SYNOPSIS

SO occupied 2.14% of ovarian teratoma, where 12.0% and 4.7% of SO may transform into OSC and MSO, respectively, and had excellent survival outcomes.

Synchronous thyroid cancer and malignant struma ovarii: concordant mutations and microRNA profile, discordant loss of heterozygosity loci

BACKGROUND

Struma ovarii is an unusual ovarian teratoma containing predominantly thyroid tissue. Less than 10% of cases undergo malignant transformation in the thyroid tissue and are considered malignant struma ovarii (MSO). MSO have been reported with concurrent thyroid lesions, but molecular data is lacking.

CASE PRESENTATION

A 42-year-old female developed MSO and synchronous multifocal subcentimeter papillary thyroid carcinoma (PTC). The patient underwent a salpingo-oophrectomy, thyroidectomy, and low-dose radioactive iodine ablation. Both the thyroid subcentimeter PTC and MSO were positive for BRAF V600E mutation, and microRNA expression profiles were similar across all tumor deposits. However, only the malignant component demonstrated extensive loss of heterozygosity (LOH) involving multiple tumor suppressor gene (TSG) chromosomal loci.

CONCLUSIONS

We present the first reported case of MSO with synchronous multifocal subcentimeter PTC in the thyroid containing concordant BRAF V600E mutations and resulting with discordant LOH findings. This data suggests that loss of expression in tumor suppressor gene(s) may be an important contributor to phenotypic expression of malignancy.

Follicular carcinoma originating from struma ovarii: A case report

INTRODUCTION

Follicular carcinoma originating from struma ovarii is a clinically rare low-grade malignant tumor. The pathological diagnosis of ovarian thyroid follicular carcinoma is predominantly based on the infiltrative growth and vascular involvement of tumor cell nests of different sizes in the ovarian parenchyma.

PATIENT CONCERNS

Here we present a case of this malignancy in which the bilateral ovaries, right oviduct wall, myometrial surface, omentum, and bladder reflex were extensively involved Microscopically, the thyroid follicles in this case showed infiltrative growth of nodules of different sizes in the ovarian stroma.

DIAGNOSIS

The epithelial layer of the follicles was atypical, but with no nuclear features of papillary thyroid carcinoma such as nuclear groove and nuclear pseudoinclusions. Immunohistochemistry showed positive expression of thyroglobulin, thyroid transcription factor-1, and cytokeratin19, with a Ki-67 index of 5% +. Immunohistochemical results combined with microscopic morphology allowed a diagnosis of follicular carcinoma originating from struma ovarii.

INTERVENTIONS

After exclusion of contraindications to surgery, the patient underwent surgical exploration on July 26, 2022, during which frozen pathological examination was performed.

OUTCOMES

The patient recovered well and was discharged. At the first follow-up visit in October 2022, the patient had an excellent survival.

CONCLUSION

The analysis of the microscopic morphological characteristics and immunohistochemistry deepened our understanding of the pathological characteristics of ovarian and thyroid follicular carcinoma, and further provides a diagnostic reference for other clinicians who will encounter these conditions in the future.

Malignant Struma Ovarii (Papillary Carcinoma) with Hyperthyroidism: A Case Report and Literature Review

Malignant struma ovarii (MSO) is an extremely rare monodermal ovarian teratoma. Preoperative diagnosis and intraoperative freezing diagnosis are exceedingly difficult due to the rarity of the disease and its clinically noncharacteristic manifestations with less than 200 reports in the current literature. In this paper, a case of MSO (papillary carcinoma) with hyperthyroidism was discussed in terms of its epidemiology, clinicopathology, molecular features, treatment, and prognosis.

Tyrosine kinase inhibitor treatment and long-term follow-up for metastatic malignant struma ovarii

Metastatic malignant struma ovarii (MMSO) is a very rare disease (in the United States, less than one case in 10 million females annually). However, this incidence rate is due to a paucity of data regarding diagnosis, treatment, and follow-up. Herein, we describe the case of a 14-year-old female who presented with MMSO, which later metastasized and was followed up on for over 10 years. The patient underwent right oophorectomy surgery and was then treated with a combination of radioactive iodine followed by iodine scans to detect the absorption of radioiodine in the metastatic sites, and radiation therapy to treat skeletal lesions. She subsequently received treatment with the tyrosine kinase inhibitors (TKIs), sorafenib and then lenvatinib, as treatments for advanced disease, thereby achieving long-term disease stability. This case report, which adds to the limited data available on MMSO treatment, suggests that patients treated with a combination of radioactive iodine, radiation therapy, and TKIs can result in good responses and long-term overall survival.

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.

Struma ovarii with contralateral ovarian teratoma: A case report

Struma ovarii (SO) is a rare form of ovarian teratoma in which the thyroid tissue constitutes over 50% of the tumor. SO comprise 1% of all ovarian tumors. We report the case of a 61-year-old woman who was admitted to the hospital because of frequent urination and dysuria. Abdominal magnetic resonance imaging revealed a mass measuring approximately 16 cm in diameter in the right adnexal area. After transabdominal bilateral adnexectomy, pathological examination revealed a teratoma of the ovary on the right and goiter of the ovary with focal thyroid cancer on the left side. Subsequent total thyroidectomy was performed, and no cancer was found on pathological examination. The patient was treated with thyroxine for a long time after the operation, and there was no recurrence 3 years after diagnosis.

Management of malignant struma ovarii: is aggressive therapy justified? Case report and literature review

Background

Struma ovarii (SO) is a rare ovarian teratoma containing predominantly thyroid tissue. In rare situations SO may develop malignancy. Most cases of malignant struma ovarii (MSO) are diagnosed after surgical removal, based on histopathological examination. There are still controversies regarding the extent of surgery and postoperative management in MSO, due to its unpredictable behavior, possible risk of metastasis and relatively high rate of recurrence.

Case Presentation

We present the case of a patient diagnosed with a right ovarian cyst discovered incidentally during routine ultrasound examination. Its rapid growth and pelvic MRI raised the suspicion of a neoplastic process. She underwent total hysterectomy and bilateral adnexectomy. The anatomopathological diagnosis was MSO with follicular variant of papillary thyroid carcinoma. Prophylactic total thyroidectomy was performed, followed by radioactive iodine ablation (RAI), and suppressive therapy with levothyroxine. At 1 year follow-up, the patient was disease free.

Conclusions

Even if latest literature reports consider that completion of local surgery with total thyroidectomy and RAI might be too aggressive in cases of MSO without extraovarian extension, in our case it was decided to follow the protocol for primary thyroid carcinoma, in order to reduce the recurrence risk.

Malignant Clinical Course of "Proliferative" Ovarian Struma: Diagnostic Challenges and Treatment Pitfalls

Struma ovarii (SO) is a monodermal teratoma predominantly composed of thyroid tissue (TT) showing benign, “proliferative”, or malignant histology. By imaging, a 38-year-old patient with lower backache revealed a 6.2-cm vertebral lesion (L5). Core biopsy showed well-differentiated TT without features of papillary carcinoma. A 3.5-cm left ovarian mature teratoma (lacking TT) and peritoneal nodules (showing well-differentiated TT) were also identified and surgically removed. Thyroid ultrasound and cytological examination resulted negative. Four years before, left ovarian cystectomy was performed for a histologically “proliferative” SO. According to the malignant clinical course and WHO classification, this case was overall reassessed as a recurring well-differentiated follicular carcinoma arising in SO (WD-FC-SO), despite lacking malignant histological features in any specimens. Immunophenotype: TTF-1+/PAX-8+/thyroglobulin+/CK7+/chromogranin-/synaptophysin-/inhibin-/calretinin-/HNF1B-; Ki-67 index < 5%. Polymerase chain reaction analysis resulted negative for BRAFV600E mutation. The patient refused further treatments, without recurrence after 17 months. The clinical behavior of SO may be unpredictable. Histologically benign or proliferative strumas extraordinarily metastasize, while SO with malignant features may not recur. The exceptional evidence of peritoneal implants of well-differentiated TT (peritoneal strumosis) in patients with histologically benign SO represents a metastasis of WD-FC-SO (like in our case). A multidisciplinary approach including clinical, laboratory, radiologic, and histopathological data is required.

Metastatic malignant struma ovarii: a case report and review of the literature on the management of malignant struma ovarii

OBJECTIVES

To present a case of metastatic struma ovarii, to review the literature on malignant struma ovarii and to discuss the management in locoregional and metastatic disease.

METHODS

We present a case of an 82-year-old patient with a malignant struma ovarii and liver metastasis. The patient was treated with pelvic surgery, total thyroidectomy, radioactive iodine therapy and TSH suppression therapy with levothyroxine. We performed a PubMed search for case reports of metastatic struma ovarii.

RESULTS

43 cases of metastatic struma ovarii were identified. 53.5% of patients presented with metastatic disease at diagnosis. Mean time to development of metastasis was 6.9 years in the group with initial locoregional disease. First-line treatment was pelvic surgery in all patients. Thyroidectomy was performed in 83.7% of patients, subsequent radioactive iodine therapy in 79.1%, followed by TSH suppression therapy in 46.5% of patients. Mean time of follow-up after diagnosis of metastases was 3.6 years, ranging from 0.5 to 24 years. At the end of the follow-up, 51.1% of patients were free of disease, 34.9% were alive with disease, 7.0% died of disease and 7.0% were lost to follow-up.

CONCLUSION

The majority of patients with metastatic struma ovarii were treated with pelvic surgery, total thyroidectomy and radioactive iodine therapy. Suppression of TSH with levothyroxine was given in less than half of the patients. In non-metastatic setting, the same approach could be considered depending on the patient profile.

Case Report: Recurrent Malignant Struma Ovarii With Hyperthyroidism and Metastases, A Rare Case Report and Review of the Literature

Background: SO (Struma ovarii) is a rare form of ovarian teratoma which originates from ovarian dermoid cysts. Due to the rarity of this disease, relevant studies might not be sufficiently documented, especially cases with hyperthyroidism and multiple metastases.

Case Presentation: A 40-year-old female patient was admitted to our hospital due to management of early pregnancy along with a recurrent abdominal and pelvic mass. Contrast-enhanced CT images showed an irregular mass (10.7 × 8.6 × 12.8 cm) located in the right side from the hypogastrium to the pelvic cavity and another mass (3.8 × 3.7 cm) in the liver. Laboratory examination showed that CA125 (Carbohydrate Antigen-125) was 118.10 U/mL, Tg (thyroglobulin) was >300 ng/ml, FT4 (free thyroxine) was 22.11 pmol/L, and TSH (thyroid-stimulating hormone) was <0.004 mIU/L. She subsequently underwent liver mass dissection, omentectomy, tumor dissection, peritoneal nodule resection, as well as rectal anterior wall nodule resection. The patient was diagnosed with malignant SO (papillary type) along with multiple metastases. Also, we conducted a literature review based on 290 SO cases from 257 articles.

Conclusion: This study showed that malignant SO might be prone to relapse and metastasize (a metastatic rate of 52.94%) and therefore aggressive management might need to be recommended for malignant SO. Also, laparotomy might need to be recommended for large tumors that cannot be resected by laparoscopic surgery since these tumors might be prone to rupture and thus produce peritoneal implants. Furthermore, Graves’ disease might need to be considered in the differential diagnosis.

Metastatic follicular carcinoma arising from struma ovarii

Struma ovarii (SO) is an uncommon monodermal teratoma predominantly composed of mature thyroid tissue. Approximately 5% of SO are malignant; however, metastases are rare. A single female in her 40s, with a medical history of Graves' disease and bilateral cystectomy 10 years prior for right endometriotic cyst and left SO, presented with an enlarging abdominal mass for 4 months. Ultrasound pelvis showed a 13.8 cm left adnexal heterogeneous solid-cystic mass with internal septations and vascularity. She underwent open left salpingo-oophorectomy and resection of fibrous nodules from the right infundibulo-pelvic ligament and fallopian tube. Histology showed highly differentiated metastatic follicular carcinoma. She subsequently underwent total thyroidectomy, total hysterectomy, right salpingo-oophorectomy, tumour debulking and omentectomy followed by radioactive iodine treatment. Four-year follow-up did not show tumour recurrence or metastases. Due to its rarity, there are no well-established guidelines for the management and follow-up of metastatic follicular carcinoma arising from SO.

Malignant struma ovarii with papillary carcinoma combined with retroperitoneal lymph node metastasis: A case report

BACKGROUND

Struma ovarii is a rare specific ovarian tumor. It is a highly differentiated monodermal teratoma with a malignant transformation rate as low as 5%. Thus, malignant transformation and metastasis are extremely rare. The clinical manifestations of this disease are not typical and are easily misdiagnosed.

CASE SUMMARY

A 55-year-old female patient had a history of pain in the right hepatic region for approximately 1 year. Computed tomography and magnetic resonance imaging showed a solid cystic mass in the right adnexal region and a solid mass in the right retroperitoneum. The patient underwent surgical resection, and the combined morphological and immunohistochemical results led to the final diagnosis of right struma ovarii with papillary carcinoma and right retroperitoneal lymph node metastasis.

CONCLUSION

Malignant struma ovarii with distant metastasis is extremely rare, and the clinical manifestations of this disease are nonspecific. Accurate preoperative diagnoses are difficult to obtain, and pathological examination is the gold standard for diagnosing this disease.

Survival Outcomes and Prognostic Predictors in Patients With Malignant Struma Ovarii

Background: Malignant struma ovarii (MSO) is an extremely rare ovarian malignant tumor and there is limited data on the survival outcomes and prognostic predictors of MSO. The objectives of this study were to investigate the disease-free survival (DFS), overall survival (OS), and disease-specific survival (DSS) rates of patients with MSO, and also evaluate the prognostic factors in this population.

Methods: A retrospective study was conducted and 194 cases of MSO were selected. DFS was assessed by the logistic regression, OS by the Kaplan–Meier method, and DSS was evaluated by the Cox regression.

Results: The median age of these patients was 46.0 years; 142 cases (73.2%) were confined to the ovary and 52 cases (26.8%) had extraovarian metastasis at the initial diagnosis of MSO. During the follow-up, 75.3% of these patients showed no evidence of disease and 18.0% were alive with disease. Only 13 deaths occurred, with 10 attributed to MSO. The 5, 10, and 15-year OS rates were 91.4, 87.7, and 83.5%, respectively. The 5, 10, and 15-year DSS rates were 93.8, 90.0, and 85.7%, respectively. Logistic regression revealed that International Federation of Gynecology and Obstetrics (FIGO) stage IV was the only risk factor for DFS [p < 0.001; odds ratio (OR) 7.328; 95% CI 3.103–16.885, FIGO stage IV vs. stage I; p = 0.021; OR 4.750, 95% CI 1.264–17.856, FIGO stage IV vs. stage II-III]. The multivariate Cox regression analysis showed that poor differentiation was the only risk factor for both OS (p = 0.005, OR 6.406; 95% CI 1.730–23.717) and DSS (p = 0.001, OR 9.664; 95% CI 2.409–38.760), while age ≥45 years was the prognostic predictor for OS (p = 0.038, OR 4.959; 95% CI 1.093–22.508).

Conclusion: Survival outcomes were excellent in patients with MSO, irrespective of the treatment strategy, FIGO stage IV, age ≥45 years, and poor differentiation of tumors were the independent risk factors.

Retrospective Diagnosis of Malignant Struma Ovarii After Discovery of Pulmonary Metastasis

Objective

Malignant struma ovarii diagnosis is challenging due to its benign histologic appearance and rarity. We present a case of struma ovarii determined malignant after pulmonary metastases were incidentally discovered.

Methods

A 29-year-old female with a history of benign struma ovarii presented to the emergency room with right lower abdominal pain. Abdomen and pelvis computed tomography showed multiple bilateral pulmonary nodules, which demonstrated well-differentiated thyroid tissue on biopsy. Review of prior ovarian pathology identified features of highly differentiated thyroid carcinoma. Laboratory studies were negative for thyroglobulin (TG) antibodies, thyrotropin was 0.713 mIU/L, and TG was 169 ng/mL. The patient underwent total thyroidectomy, revealing a 0.3 cm follicular variant papillary thyroid microcarcinoma without lymphovascular invasion. An I-123 whole-body scan revealed bilateral metastases in the thigh muscles.

Results

I-123 whole-body scan after receiving I-131 therapy demonstrated uptake in the lungs, thyroid bed, and bilateral thighs. A computed tomography scan 5 months later revealed a decreased size of the pulmonary nodules.

Conclusions

Careful histologic examination is key in making an early diagnosis of malignant struma ovarii. It requires a high index of suspicion and close histologic examination to identify malignant features, mainly the presence of cytologic overlapping ground-glass nuclei and mitotic activity or vascular invasion. Additionally, a thorough review of the imaging is needed to identify any abnormal findings suggestive of metastases. Our case demonstrates that this diagnosis may be made retrospectively after the discovery of metastases and patients can have excellent response to I-131 therapy despite a relatively low TG level.

Malignant struma ovarii: From case to analysis

AIM

To evaluate the clinico-pathologic features, treatment options, prognostic factors, and survival outcomes of malignant struma ovarii based on a systematic literature review in association with our case study.

METHODS

A systematic review of the medical literature was performed to identify articles about malignant struma ovarii from January 1983 until July 2020. We evaluated 178 cases.

RESULTS

The 5-year progression-free survival (PFS) and overall survival (OS) of the entire cohort was 72.5% and 91%, respectively. In univariate analysis, younger age (<43 years), whole strumal cyst diameter >95 mm, presence of a histologic type other than papillary classic-type thyroid carcinoma within the tumor and lymphovascular space invasion were related to poor PFS. Patients who received radioactive iodine ablation (RIA) before the treatment failure had significantly higher PFS than those who did not receive RIA (94.9% vs. 64.8%, p = 0.041, respectively). In univariate analysis, PFS was significantly higher in patients who underwent gynecologic surgery followed by thyroidectomy and RIA compared with those who had surgical treatment only (94.5% vs. 64.3%, p = 0.05, respectively). However, this result could not be identified as an independent prognostic factor in multivariate analysis (p = 0.207). Younger age and absence of capsular involvement were related to significantly increased OS. Histologic type was the only independent prognostic factor for PFS (hazard ratio: 3.30, 95% confidence interval: 1.122-9.748; p = 0.030) CONCLUSION: The most common histologic subtype was the papillary classic type. The presence of a histologic type other than the classic papillary thyroid carcinoma within the tumor was an independent adverse prognostic factor.

Malignant struma ovarii with late recurrence harbouring high microsatellite instability

Struma ovarii (SO) is a rare ovarian teratoma containing abundant mature thyroid tissue. Malignant transformation is even less common and distant metastasis is documented in about 5%-10%. The time from diagnosis of primary SO to metastatic disease varies. As malignant SO is rare, there are no uniform diagnostic criteria or treatment guidelines. Management is usually extrapolated from that of thyroid malignancy. We report a patient who relapsed 12 years from the initial diagnosis and metastasised to the lungs 5 years after the first recurrence. Our patient was treated with total thyroidectomy followed by radioactive iodine, and retreated on progression in the lungs. The tumour harboured high microsatellite instability and treatment with programmed cell death protein 1 inhibitor was initiated. This case shows the long latency of SO with the rare phenomenon of metastasis. It also highlights the importance of molecular testing for rare cancers such as this.

Clinical characteristics and survival outcomes of malignant struma ovarii confined to the ovary

Background

Malignant struma ovarii (MSO) is a unique type of ovarian malignancy that data on the survival outcome is limited and management strategy remains controversial due to its extreme rarity.

Methods

To investigate the clinical characteristics and treatment options in patients with MSO confined to the ovary, while also evaluating the recurrent-free survival (RFS) and overall survival (OS) rate in this population, a retrospective study was conducted. One hundred twenty-five cases of MSO confined to the ovary were enrolled and their clinical characteristics, treatment strategies, and results of follow-up were analyzed. OS and RFS were assessed by Kaplan-Meier analyses and Cox regression models.

Results

The most common pathological subtype in this cohort was papillary carcinoma (44.8%). Other reported subtypes, in order of prevalence, were follicular variant of papillary carcinoma, follicular carcinoma, and mixed follicular-papillary carcinoma. Surgical treatment options varied in this cohort that 8.0% of the patients received ovarian cystectomy, 33.6% underwent unilateral salpingo-oophorectomy (USO), 5.6% received bilateral salpingo-oophorectomy (BSO), 21.6% received total abdominal hysterectomy with BSO (TAH/BSO), and 17.6% were treated with debulking surgery; 20.0% of them received radioiodine therapy (RAI). Twenty-seven patients experienced recurrence with a median RFS of 14.0 years (95% confidence interval [CI], 9.5–18.5). The 5-year and 10-year recurrent rate were 27.1, 35.2%, respectively. Eight patients died during follow-up, with five attributed to MSO; the 5-year, 10-year, and 20-year OS rate was 95.3, 88.7 and 88.7%, respectively. However, the univariate and multivariate Cox regression showed no potential risk factor for RFS and OS.

Conclusion

Patients with MSO confined to the ovary had an excellent survival outcome, despite varied treatment strategies, and the recurrent rate was relatively high. We recommend USO as the preferred surgical option in this population since more aggressive surgery does not improve outcomes and the benefits of RAI are uncertain.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-08118-7.

The Clinical and Pathological Characteristics of Malignant Struma Ovarii: An Analysis of 144 Published Patients

The objective of this study is to summarize the clinical and pathologic characteristics of malignant struma ovarii to facilitate the early diagnosis and treatment of this disease. All 144 patients were females from 27 countries. The mean age of the patients at diagnosis was 42.6 years. Overall, 35.71% of the patients underwent unilateral oophorectomy, 58.57% of the patients underwent bilateral oophorectomy, 5.72% of the patients were not ovariectomized, and 38.57% of the patients received radioactive iodine treatment with an average dose of 158.22 mCI each time. “Impure” types accounted for 70.19% of the cases, while pure types accounted for 29.81% of the cases. Among these cases, papillary thyroid carcinoma accounted for 50.00%, follicular thyroid carcinoma accounted for 26.47%, follicular variant of papillary thyroid carcinoma accounted for 18.63%, papillary and follicular mixed thyroid carcinoma accounted for 2.94%, anaplastic carcinoma accounted for 0.98%, and medullary carcinoma accounted for 0.98%. In total, 21 patients (51.22%) had elevated CA125. More than half of the patients (51.94%) had metastasis outside the ovary. The most common metastatic site was the pelvic cavity. The misdiagnosis rate was 17.27%. Mortality was related to metastasis and the cancer type. Gene mutations were found in the NRAS, KRAS, BRAF, and KIT genes and were similar to those in thyroid carcinoma, but some patients (37.5%) did not exhibit any gene mutations. Regardless of the treatment received, the survival rate is high. Treatment could initially include ovariectomy; however, in cases with metastasis and iodine uptake of the metastatic tumor, thyroidectomy, radioactive iodine therapy, and thyroid hormone inhibiting therapy are indicated.

Malignant struma ovarii: surgical, histopathological and survival outcomes for thyroid-type carcinoma of struma ovarii with recommendations for standardising multi-modal management. A retrospective case series sharing the experience of a single institution over 10 years

PURPOSE

Struma ovarii is rare, accounting for 0.3-1% of ovarian tumours. Malignant transformation may occur, most often into papillary thyroid carcinoma. There is a paucity of data pertaining to malignant struma ovarii. This paper shares a decade of experience of a single institution in the management of this rare ovarian cancer, exploring the characteristics of this tumour and suggesting a standardised approach to treatment and follow-up.

METHODS

All patients treated for malignant struma ovarii within a large cancer centre over one decade were identified and data collected retrospectively on presentation, diagnosis, management, follow-up and survival outcomes. A literature review was also undertaken.

RESULTS

Eleven cases of malignant struma ovarii were managed in the Oxford Cancer Centre between 2010 and 2019, 6 of which were of papillary thyroid carcinoma sub-type. No cases were correctly diagnosed pre-operatively. All patients had stage I disease and were managed surgically-but with variation in radicality. Patients identified as high-risk based on final histopathology underwent additional thyroidectomy and radio-active iodine ablation therapy. One case of synchronous malignancy of the thyroid gland proper was identified. No disease recurrence occurred.

CONCLUSION

Malignant struma ovarii present a diagnostic challenge. Multi-disciplinary team (MDT) input is essential. Unilateral salpingo-oophrectomy may be adequate if stage I; reserving more radical surgery for advanced disease. Histopathological risk-stratification should be used to identify those most likely to benefit from adjuvant thyroid-targeting therapies. Patients require follow-up, anticipating an overall good prognosis.

Malignant struma ovarii: next-generation sequencing of six cases revealed Nras, Braf, and Jak3 mutations

PURPOSE

Struma ovarii (SO) is a highly specialized ovarian teratoma, consisting of thyroid tissue. Rarely, carcinomas histologically identical to their thyroid counterparts may occur, and are comprehensively defined as malignant struma ovarii (MSO). Their optimal management is controversial, and the molecular profile of the malignant counterpart in the ovary is incompletely known. In this study, the clinicopathological and molecular features of six MSO from different Italian Institutions were analysed, to explore genetic profiles of potential therapeutic interest.

METHODS

The histopathological features and immunoprofile (according to the known markers Galectin-3, HBME1, cytokeratin 19 and CD56) were reviewed. In addition, all cases underwent genetic analysis with a next-generation sequencing (NGS) hot spot cancer panel detecting mutations in 50 genes involved in cancerogenesis. RET/PTC rearrangements and TERT promoter alterations were also evaluated.

RESULTS

Papillary carcinoma in all similar to its thyroid counterpart was found in five of six cases, including classical (two tumors) and follicular variant (three tumors) types. The last case was a poorly differentiated carcinoma. An activating gene mutation, was detected in five of six cases, including two NRAS, two BRAF, and one JAK3 oncogene mutations. No alterations were found in the other panel genes, nor in TERT promoter, or in RET chromosomal regions.

CONCLUSIONS

MSO is a rare condition. Papillary carcinoma is the predominant malignant type, sharing both histomorphological and molecular features of its thyroid counterpart. Interestingly, the single case of poorly differentiated carcinoma displayed a JAK3 mutation. The presence of such driving mutation could be of potential interest in guiding postoperative treatment.

FIGO Stage IV and Age Over 55 Years as Prognostic Predicators in Patients With Metastatic Malignant Struma Ovarii

Introduction: Metastatic malignant struma ovarii (MSO) is an extremely rare disease that lacks treatment consensus and accurate prognosis. The objective of this study was to present the clinical, pathological, and treatment characteristics of metastatic MSO, while also investigate the overall survival (OS) rate and factors affecting prognosis in this population.

Materials and Methods: A total of 79 cases of metastatic MSO were reviewed, including four cases of metastatic MSO from our hospital and 75 cases selected from the literature. Logistic regression was used to identify potential factors affecting disease free survival (DFS). The Kaplan-Meier method and log-rank test were used to determine OS; further Cox regression was used to evaluate factors affecting OS.

Results: The mean age of all the patients at diagnosis was 43.8 years. The most common metastatic sites were peritoneum, bone, liver, omentum and lung in descending order. Only two patients (2.6%) coexisted with local primary thyroid cancer. Follicular carcinoma (41.8%) as the most prevalent subtype, followed by papillary carcinoma, follicular variant of papillary carcinoma, and mixed follicular-papillary carcinoma. 36.7% of the patients received conservative surgery, 43.0% of them underwent aggressive surgery, and 15.2% of them did not receive any surgery. 74.7% of patients who received adjuvant therapy underwent radioiodine therapy (RAI). Logistics regression revealed that FIGO stage IV was the only prognostic factor in predicting DFS (P = 0.002; Odds Ratio [OR] 5.333; 95% confidence interval [CI]: 1.839–15.471). Only seven deaths occurred. The OS rates at 5, 10, 15 years were 89.3, 82.4, 65.9%, respectively. Multivariate analysis showed age over 55 years (P = 0.006; OR 9.362; 95%CI: 1.895–46.246) was the only risk factor for OS.

Conclusion: Patients with metastatic MSO have an excellent disease-specific OS rate, FIGO stage IV and age over 55 years were two factors affecting disease prognosis. Conservative surgery with residual ablation by RAI after total thyroidectomy should be preferred since the benefits of aggressive surgery are uncertain.

Papillary Thyroid Cancer in a Struma Ovarii in a 17-Year-Old Nulliparous Patient: A case Report

Introduction: Struma ovarii accounts for 2% of mature teratomas. Struma ovarii is diagnosed when thyroid tissue accounts for >50% of the teratoma. Malignant transformation is rare, occurring in <5% of struma ovarii cases. Case presentation: A 17-year-old patient was diagnosed with papillary thyroid cancer in struma ovarii. The patient exhibited menstrual disorders. Abdominal and pelvic CT revealed a 17 cm mass in the left adnexa. Laparoscopic removal of the left adnexa with enucleation of right ovarian cysts was performed. Histopathological diagnosis was a follicular variant papillary carcinoma measuring 23 mm in diameter. Immunohistochemical positive expression of CK19, TTF-1, and thyroglobulin (Tg) confirmed the diagnosis. Molecular analysis detected the BRAF K601E mutation in ovarian tumor tissues. Preoperative serum Tg concentration was >300 ng/mL, which decreased to 38.2 ng/mL after gynecological surgery with undetectable anti-Tg antibodies. The patient underwent total thyroidectomy with no cancer detected on histopathological examination. The patient was treated with I-131 and showed no recurrence 4 years after the diagnosis. Conclusions: Malignant struma ovarii is diagnosed by surgery. Because papillary carcinoma in struma ovarii is rare and there are no guidelines regarding the management of this type of cancer, therapeutic decisions should be made individually based on clinical and pathological data.

Does every classical type of well-differentiated thyroid cancer have excellent prognosis? A case series and literature review

Introduction: The classical type of well-differentiated thyroid cancer (WDTC) is the most common endocrine tumor with generally excellent prognosis. WDTC of the WHO stage 1 classification metastasizing to the vertebral column is not often seen for this neoplasm. Here, I present a case series of 14 individuals with aggressive classical type of WDTC. Methods: To identify the most aggressive cases of classical type WDTC, I reviewed the medical records of 4,327 patients consecutively admitted and surgically treated in a single institution for thyroid pathology in the years 2008-2016. Demographic, pathological and outcome data were collected and reviewed. Results: During the study period, 14 (4.02%) patients with aggressive forms of the classical type of WDTC were reviewed: 10 (2.87%) cases with papillary thyroid cancer (PTC) and 4 (1.14%) with follicular thyroid cancer (FTC). The median age at diagnosis was 61 years (31-84 years). Aggressive features such as extrathyroid extension 11/14 (78.57%), positive surgical margins 11/14 (78,57%), lymph node metastases 7/14 (50%), multifocality 6/14 (42.85%), regional tissue infiltration 11/14 (78.57%) and distant metastases 4/14 (28.57%) were observed. Long-term follow-up (median 40 months) demonstrated a high rate of locoregional recurrence in 12/14 (85.71%) individuals. Pulmonary and other distant metastases were observed in 4/14 (28.57%) patients, with mortality in 3/14 (21.42%) individuals. Conclusion: In patients with classical type of WDTC characterized by excellent prognosis, extremely aggressive entities might be observed, making WDTC in some cases an unpredictable tumor.

Unusual Case of Malignant Struma Ovarii and Cervical Thyroid Cancer Preceded by Ovarian Teratoma: Case Report and Review of the Literature

Objective

To present a rare case of malignant struma ovarii (MSO) and synchronous thyroid cancer, review the medical literature, and present the latest trends in management.

Methods

The case of a woman with MSO and concomitant thyroid cancer is presented, including clinical presentation, treatment, and follow-up care. A search of the English-language literature was conducted using MEDLINE and Google Scholar data bases.

Results

We found 10 publications (one abstract) describing 10 patients with MSO and concomitant thyroid cancer. Six additional patients were reported by a study that analyzed the SEER (cancer registry) database. The median age of women was 42 years, with the majority of them presenting with abdominal symptoms. Histologically, most tumors were papillary carcinomas in both organs. In 5 patients, there was extrathyroidal tumor extension at time of surgery.

Conclusion

MSO can occasionally coexist with highly aggressive eutopic thyroid cancer. Although this concurrence is even rarer than MSO, clinicians should routinely investigate for possible synchronous thyroid cancer in all cases of MSO and also consider aggressive postoperative treatment including thyroidectomy and radioiodine ablation therapy in cases of MSO.

Extensive peritoneal implant metastases of malignant struma ovarii treated by thyroidectomy and 131I therapy: A case report

RATIONALE

Malignant struma ovarii is extremely rare in the clinic. The diagnosis and modalities of treatment are still controversial. Here we describe a case of extensive peritoneal implant metastasis originating from malignant struma ovarii discovered 14 years after ovariectomy and chemotherapy.

PATIENT CONCERNS

A 48-year-old female was admitted to our clinic due to hematochezia with a past history of left malignant struma ovarii. Enhanced computed tomography (CT) examination suggested multiple metastasis nodules in the abdomen and pelvic cavity.

DIAGNOSES

Laparoscopy biopsy results of intraperitoneal nodules showed a metastasis of papillary thyroid carcinoma. While pathological examination after total thyroidectomy showed no definite malignant tumor component in the thyroid tissue. Finally, combined with the patient's past history of malignant struma ovarii, peritoneal implantation metastasis derived from the malignant struma ovarii was diagnosed.

INTERVENTIONS

The patient was treated by total thyroidectomy and iodine 131 (I) therapy. Post-therapy iodine scan and the single-photon emission computed tomography/computed tomography (SPECT/CT) fusion image showed iodine uptake in the distal descending colon, sigmoid colon, rectal lesions, and a larger lesion in the liver.

OUTCOME

After treatment, although the thyroid globulin remained at a high level 3 months after treatment, the patient's hematochezia was relieved.

LESSONS

Therefore, thyroidectomy followed by adjuvant I treatment should be recommended in patients with malignant struma ovarii as metastatic risk is difficult to predict based on histopathologic examination.

The largest reported papillary thyroid carcinoma arising in struma ovarii and metastasis to opposite ovary: case report and review of literature

Background

Malignant struma ovarii (MSO) is a very rare, germ cell tumor of the ovary, histologically identical to differentiated thyroid cancers. Struma ovarii (SO) is difficult to diagnose on clinical basis or imaging and is mostly discovered incidentally, with few published cases in the literature.

Case presentation

A 42-year old primiparous woman presented with abdominal pain and midline pelvic palpable firm mass arising from the pelvis. Imaging showed pelvic solid cystic mass. Total abdominal hysterectomy, bilateral salpingo-oopherectomy (TAH BSO) and infracolic omentectomy were performed. Histopathology revealed left ovary papillary thyroid carcinoma (PTC) arising in SO (11 cm) and metastatic papillary thyroid carcinoma in the right ovary. Thyroid functions tests were all normal, ultrasound thyroid showed two complex nodules in the left thyroid lobe. Total thyroidectomy was decided, but the patient refused further surgical management and was lost to follow up as she left the country. We undertook a comprehensive literature search, and MSO and thyroid management data from 23 additional publications were analyzed and tabulated. This PTC MSO is probably the largest reported in the literature.

Conclusions

Among the different surgeries for MSO, TAH + BSO appears to have the best clinical outcome. However, unilateral salpingo-oopherectomy/ unilateral oophorectomy and bilateral salpingo-oopherectomy also seem effective. Ovarian cystectomy alone seems associated with higher recurrence. There remains no consensus on the associations between MSO tumor size and potential extent of metastasis, and about the management of thyroid gland. However, surveillance and thyroid gland work up to detect concurrent thyroid cancer are recommended.

Synchronous Independent Papillary Thyroid Carcinomas in Struma Ovarii and the Thyroid Gland With Different RAS Mutations

Struma ovarii is a rare ovarian teratoma predominantly composed of thyroid tissue. The simultaneous presence of thyroid carcinoma in the struma ovarii and the thyroid gland is extremely rare. It remains unclear if these carcinomas represent independent primary tumors and whether the molecular mechanisms of the tumors developing in the thyroid and ovarian tissues are similar. We present the case of a patient with two independent papillary thyroid carcinomas (PTCs) in struma ovarii and the thyroid gland that are driven by different RAS mutations. A 62-year-old woman with a history of chronic lymphocytic leukemia/small lymphocytic lymphoma was diagnosed with a pelvic mass during a CT scan. She had surgery that included removal of her ovaries. A 7.2-cm classical variant of PTC arising in a struma ovarii was identified in the right ovary. Two months after the pelvic surgery, total thyroidectomy was performed, and a small nodule (0.8 cm) in the left lobe was diagnosed as a classical variant of PTC. Molecular analysis of tissues obtained from both the malignant struma ovarii and thyroid gland was performed. RAS mutations both in the PTC located in the thyroid and ovarian tissues were identified. However, whereas the thyroid gland tumor showed an HRAS Q61R mutation, the PTC in struma ovarii harbored an NRAS Q61R mutation. In this case, the finding of distinct types of RAS point mutation in thyroid cancers at two different locations provides definitive evidence that these cancers are synchronously developed independent primary tumors.

Rare Clinical Entity: Metastatic malignant struma ovarii diagnosed during pregnancy - Lessons for management

Background

Malignant struma ovarii is an ovarian teratoma containing at least 50% thyroid tissue which has the potential to metastasize and produce thyroid hormone. Given its rarity, management strategies are not well-established. We report a case of metastatic malignant struma ovarii discovered during pregnancy with lessons for evaluation and management.

Case presentation

A 30-year-old woman who was two months pregnant was discovered to have struma ovarii with over half of the struma comprised of papillary thyroid cancer. Following tumor resection, delivery, and thyroidectomy, she underwent evaluation with stimulated thyroglobulin testing and diagnostic staging sodium iodide-131 scan (I-131), which revealed the presence of skeletal metastases. Following administration of 320 mCi I-131, post-therapy scan also showed miliary pulmonary metastases with improved ability to localize the bony and pulmonary metastases with concurrent SPECT/CT imaging. A second dosimetry-guided I-131 therapy resulted in complete resolution of pulmonary metastases; however, small foci of residual bone disease persisted. Post-therapy scans demonstrated additional findings not shown on diagnostic I-131 scans obtained prior to both her initial and second I-131 therapy.

Conclusions

SPECT/CT provides accurate anatomic correlation and localization of metastatic foci and can serve as a baseline study to assess interval response to treatment. Post-therapy scans should always be obtained when I-131 treatment is administered, as additional findings may be revealed versus low dose I-131 activity diagnostic scans. This patient had a high metastatic burden that would not have been discovered in a timely fashion with the conservative approach advocated by others. Thyroidectomy followed by a diagnostic staging radioiodine scan and a stimulated thyroglobulin level should be considered in patients with malignant struma ovarii for guiding therapeutic I-131 administration as metastatic risk is difficult to predict based on histopathologic examination.

Malignant Struma ovarii in a 30-year old nulliparous patient

Background

Struma ovarii is a rare monodermal germ cell tumor where the ovary is comprised of at least half thyroid tissue. This phenomenon may indicate an embryological origin.

Case presentation

A 30-year old nulliparous woman presented with acute right lower quadrant pain and underwent laparoscopic right salpingo-oophorectomy. The excised ovarian mass showed evidence of struma-derived papillary thyroid carcinoma. Ultrasound of the thyroid showed mild enlargement with two solid nodules. A fine needle aspirate of a thyroid nodule was positive for malignancy and a total thyroidectomy was performed. Microscopic features of the thyroid were consistent with papillary thyroid carcinoma. The two tumours were considered as synchronous independent primaries based on their histological presentation.

Conclusions

We believe that aggressive surgical management followed by radioiodine therapy is best to reduce recurrence risk and optimize survival. The broad scope of interventions needed to treat malignant struma ovarii require a strong interdisciplinary team.

Concurrent Intrathyroidal Thyroid Cancer and Thyroid Cancer in Struma Ovarii: A Case Report and Literature Review

Context

The presence of differentiated thyroid cancer in mature cystic teratomas in the ovaries is rare, and usually incidentally found on surgical pathology specimens. We present a case of simultaneous intrathyroidal thyroid cancer and thyroid cancer within a struma ovarii, presenting specific diagnostic challenges.

Case Description

A 55-year-old woman had an intrathyroidal, encapsulated 1.2-cm papillary thyroid carcinoma, follicular variant, which was resected. Laboratory studies showed an elevated thyroglobulin level of 35 ng/mL while on suppressive levothyroxine therapy. During preparation for radioactive iodine ablation, thyroglobulin increased dramatically to 3490 ng/mL. A pretreatment whole-body scan showed residual tracer uptake in the thyroid bed and increased radiotracer uptake in the pelvis that raised concern for a pelvic metastasis, given the marked thyroglobulin elevation. After ablation, the posttreatment scan showed intense focal uptake in the pelvis. Single-photon emission computed tomography-computed tomography confirmed that the tracer uptake corresponded to a right adnexal mass. The patient underwent a laparoscopic bilateral salpingo-oophorecotomy with pelvic washings. The final pathology of the right ovary showed papillary thyroid carcinoma arising in a mature cystic teratoma. In addition, there was abundant normal thyroid tissue with colloid surrounding the carcinoma, indicating a source for the dramatic rise in thyroglobulin levels and suggesting that the ovarian papillary thyroid cancer arose within the teratoma and was not metastatic disease. Thyroglobulin measurements have been undetectable for 5 years since surgery and radioiodine treatment.

Conclusions

Concurrent intrathyroidal thyroid cancer and differentiated thyroid cancer in struma ovarii are very rare, but can often be distinguished on clinical grounds.

Management dilemma of thyroid nodules in patients with malignant struma ovarii

Struma ovarii is a rare type of ovarian teratoma comprised of at least 50% thyroid tissue. While most are benign, 70% of malignant cases are diagnosed as papillary carcinoma. Management of patients with thyroid nodules following gynecologic surgery remains controversial and variable. Historically, the treatment of choice has been surgical removal to rule out ovarian carcinoma. Thyroid follow-up and further treatment options are guided by tumor characteristics. The patient in this case presented to the endocrine surgeon with multiple thyroid nodules, dysphagia and a history of struma ovarii that was surgically treated at an outside hospital. Fine needle aspiration demonstrated benign histology. However, due to compressive symptoms and uncertainty of other nodules, the patient underwent a total thyroidectomy. Due to limited published data and treatment guidelines regarding thyroid nodules in patients with a history of malignant struma ovarii, surgery was recommended to rule out papillary thyroid carcinoma and relieve the patient's dysphagia. More research focused on treatment and outcomes of struma ovarii patients with thyroid nodules is essential to establish treatment guidelines for these patients.

Evaluating the Time Interval for Presenting the Signs of Hypocalcaemia after Thyroidectomy

INTRODUCTION

Thyroidectomy is one of the most prevalent treatments for thyroid malignancies. It has very low rate of complications except the hypocalcaemia. Only a small number of studies have evaluated the clinical signs of hypocalcaemia but no study have reported the time interval between the procedure and signs of hypocalcaemia.

AIM

The aim of this study was to determine that time interval in those patients.

MATERIALS AND METHODS

Medical files of a group of patients who underwent thyroidectomy were reviewed. Demographic characteristics of the patients and the time interval to hypocalcaemia were recorded and analysed by SPSS software. p-value <0.05 was considered significant.

RESULTS

One hundred and eight patients, 65 women (60.2%) and 43 men (39.8%) with a mean age of 42.6+12.2 years were included. Perioral numbness was reported in 30 (27.8%) patients while 29 (26.8%) patients had lip numbness. Numbness in extremities and muscle spasm were found in 19 (17.6%) and 13 (12%) patients respectively. Seizure was reported in 3 (2.8%) patients. The Trousseau and Chvostek signs were found in 17 (15.7%) and 9 (8.3%) patients respectively. Only the Trousseau sign was different between the two surgical groups. The mean time interval was 41.25±11.5 hours postoperatively. However the time interval was shorter for the total thyroidectomy.

CONCLUSION

Physical examination is useful for diagnosing hypocalcaemia due to the presentation of sings during the first 48 hours of thyroidectomy. Total thyroidectomy is associated with shorter time interval.

Are we really at the dawn of understanding sporadic pediatric thyroid carcinoma?

Data from the National Cancer Institute and from the literature have disclosed an increasing incidence of thyroid cancer in children, adolescents and adults. Although children and adolescents with thyroid cancer tend to present with more advanced disease than adults, their overall survival rate is excellent; however, there is no clear explanation for the differences observed in the clinicopathological outcomes in these age groups. There has been an ongoing debate regarding whether the clinicopathological differences may be due to the existence of distinct genetic alterations. Efforts have been made to identify these acquired genetic abnormalities that will determine the tumor's biological behavior and ultimately allow molecular prognostication. However, most of the studies have been performed in radiation-exposed pediatric thyroid carcinoma. Therefore, our understanding of the role of these driver mutations in sporadic pediatric differentiated thyroid cancer development is far from complete, and additionally, there is a strong need for studies in both children and adolescents. The aim of this review is to present an extensive literature review with emphasis on the molecular differences between pediatric sporadic and radiation-exposed differentiated thyroid carcinomas and adult population.

Novel BRAF and KRAS Mutations in Papillary Thyroid Carcinoma Arising in Struma Ovarii

Papillary carcinomas of thyroid type rarely arise within struma ovarii. There are limited data on the immunohistochemical and molecular features of these tumors. Three cases of papillary carcinoma arising in struma ovarii (PCSO) were identified. The clinicopathological features were reviewed and immunohistochemical staining for HBME-1, cytokeratin (CK) 19, and CD56 was performed. Tumor DNA was sequenced for somatic mutations using a panel of 26 oncogenes, with a particular focus on BRAF and KRAS mutations. The patients were aged 22, 48, and 55 years. All cases were FIGO stage IA. Two tumors were of classical histological type, and one was a follicular variant papillary carcinoma. All tumors expressed HBME-1 and two were positive for CK19. CD56 was negative in all three cases. One tumor demonstrated a BRAF G469A mutation in exon 11, and in a second case, a KRAS Q61K double base mutation in exon 3 was detected. These mutations have not been described previously in PCSO. No mutations were detected in the benign follicular components of the tumors adjacent to the malignant papillary tissue. None of the patients had tumor recurrence on clinical follow-up (range 11 months to 8½ years). HBME-1, CK19, and CD56 are useful immunohistochemical markers of PCSO. Novel BRAF and KRAS mutations were identified in two of three tumors suggesting that mutations in PCSO may differ from those commonly identified in papillary carcinoma of the eutopic thyroid. The clinical significance of these mutations is uncertain but follow-up data in this small series support the generally good prognosis of PCSO.