Malignant Struma Ovarii With a Predominant Component of Anaplastic Carcinoma:

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.

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.