Follicular variant papillary thyroid carcinoma arising in struma ovarii

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.

Role of gene sequencing in classifying struma ovarii: BRAF p.G469A mutation and TERT promoter alterations favour malignant struma ovarii

AIMS

Struma ovarii (SO) are rare, accounting for 0.3-1% of ovarian tumours, and include benign and malignant lesions. In most cases, histology is not predictive of clinical outcome and prognosis. The prognosis of histologically malignant thyroid-type carcinomas can indeed be excellent, while SO, composed of normal thyroid tissue, can recur and are designated highly differentiated follicular carcinoma of the ovary. Clearer diagnostic criteria are therefore required.

METHODS AND RESULTS

We retrospectively studied 31 SO using DNA and RNA sequencing with pan-cancer gene panels, including eight biologically malignant SO (BMSO) defined based on ovarian serosal or extra-ovarian dissemination at presentation or during follow-up, 10 stage IA histologically malignant SO (HMSO) with thyroid-type carcinoma morphology and 13 biologically and histologically benign SO (BSO), with none of the above-mentioned characteristics. Molecular alterations were observed in 87.5% of BMSO, 70% of HMSO and 7.7% of BSO (P < 0.001). All patients with a peritoneal dissemination at presentation or during follow-up had at least one gene alteration. BRAF mutations (44.5%) were only observed in malignant forms (HMSO and BMSO) and TERT promoter alterations (25%) only in cases of BMSO. The BRAF p.G469A mutation, which is extremely rare in thyroid carcinomas, was the molecular alteration most frequently associated with malignant SO (28.5%).

CONCLUSION

Our results highlight the clinical utility of molecular sequencing in SO, based on this limited number of cases. However, as malignant SO evolve slowly, more extensive molecular studies in SO with more than 10 years' follow-up are required to draw any conclusions on the prognostic value of the associated gene alterations.

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.

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.

Identifying the Carcinogenic Mechanism of Malignant Struma Ovarii Using Whole-Exome Sequencing and DNA Methylation Analysis

Background: Since malignant struma ovarii is a very rare disease, its carcinogenic mechanism has not been elucidated. Here, we sought to identify the genetic lesions that may have led to the carcinogenesis of a rare case of malignant struma ovarii (follicular carcinoma) with peritoneal dissemination. Methods: DNA was extracted from the paraffin-embedded sections of normal uterine tissues and malignant struma ovarii for genetic analysis. Whole-exome sequencing and DNA methylation analysis were then performed. Results: Germline variants of RECQL4, CNTNAP2, and PRDM2, which are tumor-suppressor genes, were detected by whole-exome sequencing. Somatic uniparental disomy (UPD) was also observed in these three genes. Additionally, the methylation of FRMD6-AS2, SESN3, CYTL1, MIR4429, HIF3A, and ATP1B2, which are associated with tumor growth suppression, was detected by DNA methylation analysis. Conclusions: Somatic UPD and DNA methylation in tumor suppressor genes may be associated with the pathogenesis of malignant struma ovarii. To our knowledge, this is the first report of whole-exome sequencing and DNA methylation analysis in malignant struma ovarii. Genetic and DNA methylation analysis may help elucidate the mechanism of carcinogenesis in rare diseases and guide treatment decisions.

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.

Gene fusions in tumourigenesis with particular reference to ovarian cancer

Gene fusion, a genomic event that generates a novel gene from two independent genes, has long been known to be implicated in tumourigenesis and cancer progression. It has thus served as a diagnostic and prognostic biomarker in cancer, as well as an ideal therapeutic target in cancer therapy. Gene fusion can arise from chromosomal rearrangement and alternative splicing of transcripts, resulting in deregulation of proto-oncogenes or creation of an oncogenic novel gene. Largely facilitated by next generation sequencing technologies, a plethora of novel gene fusions have been identified in a variety of cancers, which leaves us the challenge of functionally characterising these candidate gene fusions. In this review, we summarise the molecular mechanisms, the oncogenic consequences and the therapeutic implications of verified gene fusions. We also discuss recent studies on gene fusions in both common and rare subtypes of ovarian tumours and how these findings can be translated to cancer therapies to benefit patients carrying these gene fusions.

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.

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.

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.

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.

Papillary Thyroid Microcarcinoma Arising Within a Mature Ovarian Teratoma: Case Report and Review of the Literature

Mature cystic teratoma is the most common kind of ovarian germ cell tumor. Malignant transformation is uncommon, with thyroid cancer rarely found. Papillary thyroid microcarcinoma has rarely been described as associated with ovarian teratomas. We report a case of a 34-year-old woman who presented with abdominal pain and an ovarian mass. After surgery, the patient was diagnosed with a follicular variant papillary thyroid microcarcinoma that arose within a mature cystic ovarian teratoma. Based on the small size of the primary lesion and patient preferences, no further treatment was performed. To our knowledge, this is the third reported case of papillary thyroid microcarcinoma arising within a mature ovarian teratoma without struma ovarii. There is no consensus on the surgical approach and postoperative management of this condition. Whether further therapy with total thyroidectomy and radioiodine ablation may be beneficial is unknown. In conclusion, papillary thyroid microcarcinoma can also arise within mature ovarian teratomas. Although a favorable prognosis is anticipated, there is limited information about its history or prognosis.

A Hormonally Active Malignant Struma Ovarii

Struma ovarii is a rare monodermal variant of ovarian teratoma that contains at least 50% thyroid tissue. Less than 8% of struma ovarii cases present with clinical and biochemical evidence of thyrotoxicosis due to ectopic production of thyroid hormone and only 5% undergo malignant transformation into a papillary thyroid carcinoma. Only isolated cases of hormonally active papillary thyroid carcinoma developing within a struma ovarii have been reported in the literature. We report the case of a 36-year-old woman who presented with clinical signs and symptoms of hyperthyroidism as well as a left adnexal mass, which proved to be a thyroid hormone-producing, malignant struma ovarii.

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.

Follicular proliferative lesion arising in struma ovarii

Malignant struma ovarii is extremely rare and difficult to diagnose histologically, particularly in cases of follicular carcinoma. This case study is intended to describe three cases of follicular proliferative lesion arising in struma ovarii that we experienced. The first case was clearly malignant given the clinical picture of multiple recurrences, but there was little histological evidence of malignancy. Our second case featured architectural and cellular atypia and necrosis and was diagnosed as malignant despite the absence of vascular and stromal invasion. Our third case exhibited solid microfollicular proliferation without any definite evidence of malignancy (even the molecular data was negative); however, we could not completely exclude malignant potential after conducting a literature review. In cases such as our third case, it has been previously suggested that a diagnostic term recognizing the low-grade malignant potential, such as “proliferative stromal ovarii” or “follicular proliferative lesion arising in the stromal ovarii” would be appropriate.

Coexistence of malignant struma ovarii and cervical papillary thyroid carcinoma

CONTEXT

Struma ovarii is an uncommon monodermal teratoma in which thyroid tissue is the predominant element. Malignant transformation of struma ovarii is an even rarer occurrence.

CASE PRESENTATION

We describe a 42-year-old woman who underwent a total abdominal hysterectomy and bilateral salpingo-oophorectomy for a symptomatic left pelvic mass. Histology revealed malignant struma ovarii with classical papillary thyroid carcinoma expression. Ultrasonography of the cervical neck showed thyroid micronodules and a dominant 1-cm nodule in the left thyroid lobe. As the ovarian tumor was large, the patient underwent a total thyroidectomy with the intention of administering ¹³¹I therapy in an adjuvant setting. Histology of the cervical thyroid gland revealed bilateral multifocal papillary thyroid carcinoma with extrathyroidal extension and perithyroidal lymph node metastasis.

METHODS

Morphological (microscopy), immunohistochemical (Hector Battifora mesothelial cell 1, cytokeratin-19, galectin-3), and molecular (BRAF V600E, RAS, RET-PTC) characteristics and clonality analysis of the cervical thyroid and ovarian tumors were explored to distinguish them as separate malignancies.

RESULTS

The thyroid-type tumors from the cervical gland and ovary were discordant in terms of tissue histology and level of cytokeratin-19 expression. The clinical features and tumor profile results supported the independent existence of these two embryologically related, although topographically distinct, malignancies.

CONCLUSION

Our findings provided support for synchronous, albeit distinct, primary tumors in the ovary and cervical thyroid. "Field cancerization" and early genomic instability may explain multifocality in all thyroid-type tissue. In this regard, patients with malignant struma ovarii should undergo imaging of their thyroid gland for coexisting disease and thyroidectomy recommended for suspected malignancy or in preparation for radioiodine therapy.

Struma ovarii with follicular thyroid-type carcinoma and neuroendocrine component: case report

Struma ovarii (SO) is a slow-growing ovarian neoplasm with thyroid tissue as its predominant component. It is an uncommon neoplasm, usually asymptomatic with an unknown risk of malignant transformation. Due to difficulties in assessing the rare biological nature and the discrepancies in the reported cases, a consensus on the appropriate treatment has not been definitively reached.

A 50-year-old female was subjected to upper gut endoscopy which showed a 30-mm mass located in the gastric antrum, suggestive of mesenchimal tumor. Incidentally, a pelvic CT scan also documented a solid mass in the right adnexa, with morphological characteristics of ovarian neoplasm. The patient underwent gastrectomy, total hysterectomy, bilateral salpingo-oophorectomy with lymph node dissection, and omentectomy. Histology documented the presence of gastric cavernous angioma, and, in the right adnexa, foci of follicular thyroid-type carcinoma arising in SO with a well-differentiated neuroendocrine component.

Here we report and discuss the clinical and morphological presentation of follicular thyroid-type carcinoma arising in SO. The neoplasm was discovered incidentally and had a favorable clinical outcome at 1-year follow-up.

Expression of benign and malignant thyroid tissue in ovarian teratomas and the importance of multimodal management as illustrated by a BRAF-positive follicular variant of papillary thyroid cancer

BACKGROUND

The most common type of ovarian germ cell tumor is the teratoma. Thyroid tissue, both benign and malignant, may be a component of an ovarian teratoma. Here we review this topic and illustrate major features by presenting multimodal management of a patient with BRAF-positive disseminated follicular thyroid cancer arising in an ovarian teratoma.

SUMMARY

Malignant thyroid tissue is often difficult to distinguish from benign thyroid tissue arising in ovarian teratomas. Preoperatively, an elevated thyroglobulin (Tg) level, laboratory or clinical evidence of hyperthyroidism, or ultrasonography appearance of "struma pearl" should prompt referral to oncologist for surgical management of a possibly malignant ovarian teratoma. Postoperatively, tumor tissue should be referred to pathologists experienced with differentiating benign from malignant struma ovarii. Once diagnosed, treatment of this rare condition should be handled by a team of specialists with combined treatment modalities. We cared for woman with disseminated thyroid cancer arising in an ovarian teratoma whose history illustrates the complexity of managing ovarian teratomas with malignant thyroid tissue. At age 33 she had an intraoperative rupture of an ovarian cyst, thought to be struma ovarii. During her next pregnancy, pelvic masses were noted; biopsies revealed well-differentiated papillary thyroid carcinoma, follicular variant. She was euthyroid, but had elevated serum Tg levels. Surgical staging demonstrated widely metastatic intraabdominal dissemination. A thyroidectomy revealed no malignancy. A post-(131)I treatment scan revealed diffuse uptake throughout the abdomen. She then developed abdominal pain and, on computed tomography, was found to have multiple intraabdominal foci of disease. Serum Tg was 264 ng/mL while on L-thyroxine for hypothyroidism and to obtain thyrotropin suppression. A 18 fluorodeoxyglucose positron emission tomography scan showed no pathological uptake. The tumor was found to be BRAF mutation positive (K601E). She underwent extensive secondary debulking and a second course of (131)I with lithium pretreatment. Posttreatment scan revealed diffuse abdominal uptake. Six months posttherapy, the patient is asymptomatic with a serum Tg of 18.1 ng/mL.

CONCLUSIONS

Aggressive multimodal management appears to be the most promising approach for malignant thyroid tissue arising in ovarian teratomas.

A case of papillary thyroid carcinoma in struma ovarii and review of the literature

Malignancy in struma ovarii is a rare form of ovarian germ cell tumour. Because of its rarity, the diagnosis and management of the tumour have not been clearly defined. We present a case of 67- year-old female with papillary carcinoma arising in struma ovarii and review the literature on malignancy in struma ovarii cases, focusing on management of these cases.

Thyroid-type carcinoma of struma ovarii

Struma ovarii is a monodermal variant of ovarian teratoma. Thyroid-type carcinoma arising in struma ovarii is rare. The most common type is papillary carcinoma, followed by typical follicular carcinoma, and the new entity of follicular carcinoma-highly differentiated follicular carcinoma of ovarian origin; other forms occur rarely. Consensus on the surgical and postoperative treatment of patients with thyroid-type carcinoma arising in struma ovarii has not been reached. Surgical treatment ranges from total abdominal hysterectomy, plus bilateral salpingo-oophorectomy with omentectomy, to conservative surgery, involving unilateral oophorectomy or strumectomy (cystectomy) for fertility preservation. Adjuvant therapy includes external radiotherapy, chemotherapy, thyroidectomy, and radioactive iodine ablation. Thyroid-type carcinomas arising in struma ovarii, especially the newly recognized entity-highly differentiated follicular carcinoma of ovarian origin-have a favorable prognosis.