No abstract

Struma ovarii has elicited considerable interest because of its many unique features since Ludwig Pick first elucidated its relationship to teratoma in the early part of the 20th century. In this article, we report 3 cases of papillary and 1 of follicular thyroid carcinoma; 2 of these cases were associated with mature cystic teratoma. Metastases occurred in 2 patients, and 1 died of neoplasm. In regard to the occurrence of thyroid-type carcinoma in struma ovarii, precise terminology should be used, and the expression malignant struma ovarii was avoided as a diagnostic term. Upon review of the literature, papillary carcinoma and follicular carcinoma are the most frequent types of malignancy to occur in ovarian struma; other forms of thyroid carcinoma occur only rarely. The diagnostic criteria for cases of papillary carcinoma are similar to those described in the cervical thyroid gland and are based primarily on nuclear and architectural features. In reference to follicular carcinoma, invasion into the surrounding ovarian tissue, vascular invasion, or metastasis is evidence of malignancy. Histological malignancy in a struma does not necessarily equate with biological malignancy, and the majority of thyroid-type carcinomas do not spread beyond the ovary. Occasionally, metastases of ovarian struma have an innocuous histological appearance, and such cases are referred to as highly differentiated follicular carcinoma of ovarian origin (HDFCO). Because its histological appearance resembles that of nonneoplastic thyroid, HDFCO characteristically cannot be diagnosed until the neoplasm spreads beyond the ovary. In this article, we apply the term typical thyroid carcinoma to those forms of thyroid malignancy arising in ovarian struma that closely resemble the types described in the cervical thyroid gland to distinguish them from HDFCO. Typical follicular carcinoma is more aggressive than the somewhat more common papillary carcinoma, and HDFCO is the least aggressive of these tumor types. Cases of thyroid-type carcinoma arising in the ovary sometimes lack evidence of preexisting struma. The more aggressive thyroid-type neoplasms can arise in thyroid tissue within a mature cystic teratoma, or they may overgrow and replace the struma. Primary thyroid-type carcinoma must be distinguished from rare instances of ovarian metastases that originate in the cervical thyroid gland and the less differentiated forms from other ovarian neoplasms such as clear cell adenocarcinoma and tumors with an oxyphilic appearance. In the differential diagnosis with other ovarian neoplasms, cases of thyroid-type carcinoma associated with strumal carcinoid should not be diagnosed as malignant strumal carcinoid because the latter diagnosis might lead to suboptimal therapy.

No abstract

Yolk sac tumor (YST) occurs rarely in older women, either in association with a variety of ovarian epithelial tumors or, considerably less often, without an identifiable epithelial precursor. The patients often have elevated serum levels of α-fetoprotein that roughly correlate with the amount of the YST component. In postmenopausal women with an ovarian mass and elevated serum levels of α-fetoprotein, a tumor of this type should be suspected. Endometrioid carcinoma is the most common putative precursor, and the tumor is often associated with an endometriotic cyst; however, malignant Müllerian mixed tumor and mucinous neoplasms have also been reported as precursors. We report 4 cases of YST in postmenopausal women. Of the 3 cases with an identified epithelial component, 1 was serous carcinoma, another was clear cell adenocarcinoma, and the third was an admixture of endometrioid and clear cell adenocarcinoma arising from an endometriotic cyst. Although a precursor epithelial ovarian neoplasm, typically a malignancy (somatic carcinoma), is usually identified, no precursor neoplasm was observed in 1 of our cases and in 5 cases from the literature. We believe that YSTs in older women, whether or not an epithelial component is detected histologically, constitute a single entity that is distinct from YSTs in younger patients and should be treated aggressively. Neoplasms with a YST component in older women are less responsive to the chemotherapy currently used for ovarian germ cell tumors; therefore, adjuvant therapy should include platinum-based chemotherapy designed to treat both epithelial ovarian cancer and germ cell tumors. Of the 24 reported cases, including our own, 17 died of neoplasms within 25 months and another was living with disease at 2 months. However, 2 more recent patients treated aggressively with platinum-based chemotherapy designed to treat both epithelial and germ cell tumor components with stage 1 disease are living and have been disease free >1 year after operation.