Malignant struma ovarii: From case to analysis

Abstract

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.

Survival Outcomes and Prognostic Predictors in Patients With Malignant Struma Ovarii

“…Several large cohort studies showed similar OS outcomes in patients with MSO, regardless of the presence of metastatic lesions at initial diagnosis ( 9 – 12 ). In 2015, a study of 68 patients with MSO showed an OS rate of 96.7, 94.3, and 84.9% in 5, 10, and 20 years, respectively ( 9 ).…”

“…In patients ( n = 125) with MSO confined to the ovary, the OS rate was 91.5, 85.2, and 85.2% in 5, 10, and 20 years, respectively. Another systemic review showed the 5-year progress-free survival to be 72.5% ( 12 ). Our study had the largest patient cohort and confirmed the excellent prognosis of MSO.…”

“…We found that age ≥55 years was a strong risk factor for OS in patients with metastatic MSO but did not find any statistically significant predictive factor for OS in patients with MSO confined to the ovary. Ayhan et al also investigated the progression-free survival and 5-year OS rate in the patients with MSO in a literature review ( 12 ). However, this research did not assess long-term prognosis and risk factors, such as OS at 10 years or longer, as suggested by a previous study that recommended that long-term follow-up should be at least 20 years and the median recurrence interval was 14 years ( 11 ).…”

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

“…The disease is mostly benign and unilateral, and malignant transformation and metastasis are extremely rare. The malignant transformation rate is as low as 5%, and the most common malignancies are papillary carcinoma (approximately 70%) and follicular carcinoma (approximately 30%)[ 4 , 6 , 10 - 11 ]. MSO metastasizes in approximately 5%-23% of cases[ 2 , 10 ], mainly leading to lymphatic and blood metastasis and peritoneal and omental metastasis, but metastases have also been seen in the pelvis, liver, lung, etc.…”

“…Patients with both MSO and thyroid cancer are generally classified into three conditions: (1) Metastasis of thyroid cancer to the ovary; (2) Metastasis of MSO to the thyroid; and (3) Concurrent occurrence of thyroid cancer and MSO[ 11 ]. This patient had a solid cystic mass with mixed echogenicity measuring approximately 0.6 cm x 0.5 cm x 0.3 cm in size on an ultrasound examination of the left lobe of the thyroid gland.…”