What is the mortality and morbidity associated with struma ovarii?

Updated: Mar 08, 2019
  • Author: Lisa Rubinsak, MD; Chief Editor: Michel E Rivlin, MD  more...
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Malignancy is defined by various criteria in different studies, principally differing on classifying struma as either a thyroid or ovarian cancer. In the most recent World Health Organization classification, malignant struma ovarii are included in the thyroid tumor group [3] Several other types of tumors, such as Brenner tumor or cystadenoma, may also be found with a struma.

·         Malignant change seems to occur in about a third of cases. [4]

·         Metastatic spread, which follows the pattern of ovarian cancer, occurs in approximately 5% of malignant cases. [4]

·         Survival rates are excellent. [5]

Although the tumor is predominately composed of thyroid tissue, thyrotoxicosis is seen in only 5% of all cases. Only 1 case of thyrotoxicosis resulting from peritoneal strumosis has been reported. [6]

In a study of 68 patients with malignant struma ovarii, Goffredo et al found excellent disease-specific survival rates for the condition no matter which treatment—unilateral oophorectomy, bilateral oophorectomy, oophorectomy and omentectomy, or debulking surgery—was used. The report, which utilized the Surveillance, Epidemiology, and End Results (SEER) database of the National Cancer Institute, also determined that the risk of aggressive thyroid cancer in patients with malignant struma ovarii is high. The overall 5-, 10-, and 20-year survival rates in the study were 96.7%, 94.3%, and 84.9%, respectively, with only one of the deaths that occurred being attributed to malignant struma ovarii. The investigators found, however, that six patients (8.8%) were diagnosed concomitantly or subsequently with thyroid cancer, with two thirds of the thyroid cancers growing beyond the thyroid gland. All of the thyroid cancer patients were still alive at the last follow-up. [5]

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