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

Metastatic malignant struma ovarii to the pituitary presenting as a sellar mass and responding to total thyroidectomy with adjuvant radioactive iodine therapy

Malignant struma ovarii (MSO) is a rare ovarian teratoma composed primarily of thyroid tissue. Common sites of metastasis include peritoneum, bone, liver, lung, gastrointestinal tract and omentum. We present a woman in her 50s with a history of remote oophorectomy presenting with hypopituitarism and a 2.7 cm sellar mass. Trans-sphenoidal surgery for presumed pituitary macroadenoma achieved near total resection and resultant pathology surprisingly showed ectopic thyroid tissue. The patient acquired her ovarian pathology report from Southeast Asia which showed struma ovarii of the left ovary. The pituitary mass was thus determined to be a metastatic lesion from MSO. She underwent total thyroidectomy and radioactive iodine ablation therapy with good initial response and no regrowth of the tissue or emergence of distant metastases after 5 years of annual follow-up. To our knowledge, this is the first reported case of MSO to the pituitary.

Clinical use of thyroglobulin: not only thyroid cancer

Thyroglobulin (TG) is a dimeric glycoprotein produced exclusively by mature thyroid tissue and stored within the follicular lumen. It is essential for the organification of iodine and the production of thyroid hormones. The concentration of TG in the bloodstream varies between individuals and depends on factors such as thyroid mass, stimulation of the gland by thyrotropin or autoantibodies, and tissue destruction. TG is essential to monitor patients with differentiated thyroid cancer; however, its use is not limited only to this clinical entity. Measurement of circulating TG can provide better insight into numerous clinical scenarios, such as destructive thyroiditis, presence of ectopic thyroid tissue, thyroid trauma, factitious thyrotoxicosis, or iodine nutrition. Lately, TG has found its new clinical use in immune checkpoint-related thyroid dysfunction. TG measurement should be performed carefully in patients with antithyroglobulin antibodies due to possible laboratory interferences. In this review, we offer a summary of current knowledge about the clinical use of TG and the implications it brings to daily practice.

Struma Ovarii during Pregnancy

Struma ovarii is a rare type of ovarian teratoma primarily composed of over 50% thyroid tissue. Its occurrence is reported in 2-5% of all ovarian teratomas, with approximately 0.5% to 10% showing malignant transformation. Managing it during pregnancy poses significant challenges as pregnancy can promote the growth of malignant struma ovarii due to elevated levels of ovarian and pregnancy-related hormones, including estrogen, progesterone, and human chorionic gonadotrophin (hCG). Most ovarian tumors, including struma ovarii, are detected during routine ultrasonography in the first and second trimesters, often as acute emergencies. Diagnosis during pregnancy is rare, with some cases incidentally discovered during cesarean section when inspecting the adnexa for ovarian cysts. This review explores the diagnostic, management, and therapeutic approaches to struma ovarii during pregnancy.

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.

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.

Neoplasms in Struma Ovarii: A Review

Struma ovarii is a well-known ovarian teratoma made up of benign thyroid tissue. These lesions demonstrate variable, normal architecture and normal thyroid immunohistochemical staining with positivity for TTF1, PAX8, and thyroglobulin. Though most are benign, some of these lesions can also present with a malignant component. Within this article, we review the most common diagnostic malignancies including papillary thyroid carcinoma, strumal carcinoid, highly differentiated follicular thyroid carcinoma, and other thyroid carcinomas. We additionally review the use of TTF1 staining to assist in differentiating these lesions from surrounding gynecologic epithelium, which is imperative in making such diagnoses. In highlighting these entities, we hope to provide practicing pathologists with an effective and concise review of these lesions to assist in more challenging cases of struma ovarii.

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.

Mature cystic teratoma of the ovary with malignant transformation of tall cell subtype of papillary thyroid carcinoma

Malignancies rarely occur in somatic parts of mature cystic teratoma of the ovary. Squamous cell carcinoma is the most common form of cancer that can develop in mature cystic teratoma. Other less frequent malignancies include melanoma, sarcoma, carcinoid, and germ cell neoplasms. Only three cases have been reported as papillary thyroid carcinoma arising in struma ovarii. We present a unique case of a 31-year-old female patient who presented with a left ovarian cyst and underwent conservative surgical management in the form of cystectomy. Histopathological examination confirmed the diagnosis of a tall cell subtype of papillary thyroid carcinoma arising from a small focus of thyroid tissue in a mature cystic teratoma of the ovary. The patient was followed up for 60 months with an uneventful clinical course. For a better understanding of such rare cancers, collaborative retrospective studies on large databases with other medical centers are required.

The dilemma of managing thyroid gland after incidental diagnosis of malignant struma Ovarii. Is radical thyroidectomy and radioactive iodine Necessary? A case report and literature review

•Struma ovarii is a rare ovarian teratoma which consists of at least 50% thyroid tissue.•In 0.5-1% of cases the thyroid tissue in the struma ovarii undergoes a malignant transformation.•Patients should be divided into low and high-risk groups for synchronous thyroid carcinoma.•Patients with abnormalities on thyroid imaging should be considered as high-risk.•A thyroidectomy and radioactive iodine treatment can decrease the risk of recurrence.

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.

It Does Exist! Diagnosis and Management of Thyroid Carcinomas Originating in Struma Ovarii

Thyroid carcinoma originating in struma ovarii comprises a small minority of all cases of struma ovarii. Given the rarity of this diagnosis, literature to guide evaluation and management is limited. The most common carcinoma originating from struma ovarii is papillary thyroid carcinoma. Treatment includes surgery, including a fertility sparing approach if disease is confined to the ovary, with consideration of total thyroidectomy and radioactive iodine ablation for high-risk pathologic features or disease spread beyond the ovary. This review discusses the histopathologic findings, molecular pathology, clinical implications and management, and prognosis of thyroid carcinomas originating in struma ovarii.

Computed tomography, magnetic resonance imaging, and positron emission tomography/computed tomography findings for the diagnosis of malignant struma ovarii: A case report

Malignant struma ovarii (MSO) is an extremely rare disease arising from struma ovarii. Preoperative diagnosis is still challenging due to the lack of criteria for imaging findings. Herein, we report a case of MSO with suggestive imaging findings for a 50-year-old woman who presented with a pelvic tumor. The tumor did not typically show characteristic imaging findings of struma ovarii; however, the findings implied colloids of thyroid tissue within solid components on the magnetic resonance imaging (MRI) and computed tomography. Additionally, the solid components showed hyperintensity on diffusion-weighted image and hypointensity on apparent diffusion coefficient maps. Total abdominal hysterectomy, bilateral salpingo-oophorectomy, and omentectomy were performed. Histopathological examination revealed MSO of the right ovary, pT1aNXM0. The distribution of papillary thyroid carcinoma tissue corresponded to restricted diffusion area on MRI. In conclusion, the coexistence of imaging findings suggesting thyroid tissue and restricted diffusion in the solid component on MRI could indicate MSO.

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.

Papillary follicular variant thyroid cancer in a malignant struma ovarii: a report of a rare case

Summary

A 33-year-old female presented in 2013 with left flank pain. Ultrasound and MRI pelvis showed a complex mass 9 × 7 cm arising from the left ovary suggestive of ovarian torsion. She underwent a laparoscopic cystectomy, but the patient was lost to follow-up. Three years later, she presented with abdominal distension. Ultrasound and CT scan revealed a solid left ovarian mass with ascites and multiple peritoneal metastasis. Investigations showed elevated CA 125, CA 19-9. Ovarian malignancy was suspected. She underwent total abdominal hysterectomy and bilateral salpingo-oophorectomy on November 2016. The histopathology confirmed a well-differentiated thyroid cancer of ovarian origin with features of a papillary follicular variant without evidence of ovarian cancer and the thyroglobulin (Tg) level was elevated, more than 400 consistent with the diagnosis of malignant struma ovarii. The follow-up post-surgery showed normalization of CA 125, CA 19-9 and Tg. The patient underwent total thyroidectomy on January 2017. The histology was benign excluding thyroid cancer metastases to the ovary. She was started on thyroxine suppression, following which she received two ablation doses 131iodine (131I) each 5.3 GBq. The Tg remains slightly elevated at less than 10. 131I WBS showed no residual neck uptake and no distant avid metastasis. She was planned for molecular analysis which may indicate disease severity. We describe a case of malignant struma ovarii with widespread metastatic dissemination and a good response to surgery and 131I treatment without recurrence after 5 years of follow-up. The Tg remains slightly elevated indicating minimal stable residual disease.

Learning points

Malignant struma ovarii is a rare disease; diagnosis is difficult and management is not well defined. Presentation may mimic advanced carcinoma of the ovary. Predominant sites of metastasis are adjacent pelvic structures. Thyroidectomy and 131iodine therapy should be considered. The management should be similar to that of metastatic thyroid cancer.

Malignant struma ovarii with thyroid-type papillary and poorly differentiated carcinoma: a case report

Background

Malignant struma ovarii is a very rare type of gynecologic cancer. Although its most common histological subtype is a pure type of papillary thyroid carcinoma containing two components, papillary carcinoma and poorly differentiated carcinoma, malignant struma ovarii is still extremely rare. As a result, the optimal treatment for this type of tumor remains uncertain due to its rarity.

Case presentation

A 62-year-old Japanese female presented with a pelvic tumor and clinical diagnosis of malignant tumor of the ovary. She underwent complete debulking surgery, total abdominal hysterectomy, bilateral salpingo-oophorectomy, and omentectomy. The histology of the ovarian tumor revealed malignant struma ovarii with thyroid-type papillary projections and poorly differentiated carcinoma. Because of the complete resection and the absence of distant metastasis, the patient did not receive any adjuvant therapy. At 24 months after surgery, she was free of disease.

Conclusion

This is a rare case report of malignant struma ovarii, without recurrence, in which the component was papillary thyroid carcinoma mixed with poorly differentiated carcinoma. Foregoing adjuvant therapy might be one option for malignant struma ovarii in cases with complete resection and no distant metastasis. In addition, we should consider that long-term follow-up is needed for malignant struma ovarii.

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.

A rare case of highly differentiated follicular carcinoma in ovary with FGFR4 Gly388Arg polymorphism: a case report and literature review

BACKGROUND

Highly differentiated follicular carcinoma (HDFCO) is a rare form of struma-derived thyroid-type carcinoma in ovary, defined as ovarian struma spreading beyond ovary but consisting of benign thyroid tissues. No more than 30 cases of HDFCO have been reported since it was first recognized in 2008. The clinicopathologic and molecular features of HDFCO remain unclear up till now.

CASE PRESENTATION

A 38-year-old, para 1 gravida 5 woman has a long history of recurrent right ovarian cysts. Histological evaluation showed the tumor progressed from ovarian mature cystic teratoma (OMCT) to highly differentiated follicular carcinoma (HDFCO) during three relapses. Whole-exome sequencing revealed the germline FGFR4 Gly388Arg polymorphism. Repeated operations were performed to remove lesions for the first two relapses. On the third recurrence, the patient received radical surgery with subsequent thyroidectomy and radioactive iodine ablation. No evidence of disease was observed by February 2022 (8 months).

CONCLUSIONS

The germline FGFR4 Gly388Arg polymorphism may accelerate the malignant transformation of HDFCO, probably by working as a second hit in the developing spectrum.

The complex and often confusing history, histology and histogenesis of mesonephric, STK11 adnexal tumour and mesonephric-like neoplasms of the upper female genital tract (including broad ligament)

Mesonephric lesions in the female genital tract are uncommon, with those arising from the upper tract being much less frequent than those developing in the lower tract (mesonephric hyperplasia and carcinoma). The most common upper tract lesions include rete cyst/cystadenoma and female adnexal tumour of Wolffian origin (FATWO). The integration of morphological, immunohistochemical and molecular studies on FATWOs has enabled recognition of a novel entity, the STK11 adnexal tumour, which is often associated with Peutz-Jeghers syndrome (~50%) and frequently has a salivary gland morphology but an unknown origin. Similarly, 'mesonephric-like' adenocarcinoma, an entity with striking similarities to mesonephric carcinoma but currently favoured to be of Müllerian derivation based on its association with other Müllerian tumours and molecular findings, has also been recently described, and may histologically mimic both FATWOs and STK11 adnexal tumours. In this review, we provide a historical overview of upper female genital tract mesonephric proliferations and discuss mesonephric lesions, STK11 adnexal tumour, mesonephric-like adenocarcinoma, and mimickers, the most common being endometrioid carcinoma.