Malignant struma ovarii presenting with follicular carcinoma: A case report with molecular analysis

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.

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.

Highly Differentiated Follicular Carcinoma of Ovarian Origin: A Systematic Review of the Literature

(1) Background: Highly differentiated follicular carcinoma of ovarian origin (HDFCO) is an extremely uncommon neoplasm, associated with struma ovarii. There are scarce cases reported in the literature and, subsequently, no reliable conclusions on its pathophysiology, treatment, and prognosis can be drawn. The goal of this study is to enrich the literature on the topic by adding our own experience with a case, and simultaneously accumulate all cases published up to date. (2) Methods: The present review was performed in accordance with the guidelines for systematic reviews and meta-analyses (PRISMA). PubMed (1966-2022), Scopus (2004-2022), and Clinicaltrials.gov databases were screened for relevant articles published up to July 2022. (3) Results: Twenty patients with HDFCO were identified. The included patients were aged 47.15 years (range 24-74). The predominant origin was ovarian (60%) and extraperitoneal spread was confirmed in 15% of the cases. Surgical treatment varied from conservative to radical (35.3% vs. 41.2%, respectively) and the administration of supplementary therapy and thyroidectomy was not universal. Combined thyroidectomy/radioactive iodine therapy was applied in just 62.5% of the reported cases. There was one patient who demonstrated disease recurrence and lives with the disease. No disease related morbidity was reported. (4) Conclusions: HDFCO represents a low-grade malignant tumor, whose rarity does not allow for reliable conclusions. Standard treatment including complete surgical excision and supplementary treatment seems to offer a favorable prognosis in selected cases.

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.

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.

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.

Follicular carcinoma arising from struma ovarii. A case report

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. A 75-year-old hypertensive patient consulted for the sensation of a painless pelvic mass that has been progressing for six months. The abdominopelvic ultrasound showed a right lateralized abdominopelvic mass measuring 14x13x8 cm with a solid and cystic double component. The patient underwent a unilateral right adnexectomy. Grossly, the tumor was encapsulated and lobulated. On cut sections, it was solid brown whitish in color and gelatinous. On histological examination, it was formed of follicular structures of variable size filled with a dense colloid. From this goiter a malignant tumor proliferation arose, arranged in sheets, trabeculae and follicular structures, and the tumor cells were cubic or polyhedral moderately atypical with few mitotic figures. There were no papillary-like nuclear features. There was focal capsular and vascular invasion. Immunohistochemical study showed positive immunostaining of tumor cells with TTF1. Postoperative course was uneventful. The exact prognosis of thyroid-type carcinoma arising in struma ovarii is still unclear because of its rarity, inadequate follow-up, and the absence of consensus in diagnosis and treatment.

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.