Struma ovarii with atypical features and synchronous primary thyroid cancer: a case report and review of the literature

Purpose To present a case of struma ovarii with a typical features and synchronous primary thyroid carcinoma and review the available literature to guide diagnosis and management of these tumors. Methods We present a case from our hospital of a 55-year-old woman who had an adnexal mass with features concerning for papillary thyroid carcinoma and was ultimately determined to be struma ovarii with atypical features. Subsequent thyroid imaging and biopsy revealed a primary cervical thyroid carcinoma. We performed a PubMed search of published English language articles using the search terms "malignant struma ovarii," "metastatic struma ovarii," "struma ovarii with malignant transformation," "struma ovarii papillary thyroid carcinoma," "struma ovarii follicular thyroid carcinoma," and "struma ovarii with concurrent primary thyroid carcinoma." Results Literature review included 104 studies with a total of 195 patient cases. The average age at presentation was 44.9 years. 25.1% of patients had metastatic disease at presentation, and 6.2% had synchronous primary carcinomas; all of which were located in the thyroid. Conclusions Thyroid carcinoma arising in struma ovarii or mature cystic teratoma should prompt clinical evaluation and imaging of the thyroid given the possibility of synchronous primaries, metastases, and recurrence.