Optimal Strategies for the Surgical and Long-Term Management of Malignant Struma Ovarii

Struma ovarii is a rare ovarian tumor characterized by the presence of thyroid tissue, which can occasionally undergo malignant transformation. Management varies due to its rarity and the potential for malignancy. A 25-year-old female with a history of polycystic ovary syndrome (PCOS) presented with a 7 cm left ovarian cyst. Laparoscopic cystectomy revealed struma ovarii with areas of papillary thyroid carcinoma. Preoperative evaluations, including thyroid ultrasound and PET scan, showed no evidence of primary thyroid cancer or metastatic disease. Given the malignant potential, a total thyroidectomy was recommended to facilitate monitoring of thyroglobulin levels for early detection of recurrence. The patient was also scheduled for left salpingectomy and oophorectomy to reduce reoccurrence and perform a complete oncologic resection which was completed approximately 1 month following thyroidectomy and found to be negative for carcinoma. Struma ovarii requires careful management due to its potential for malignancy. Proactive surgical intervention and regular monitoring are critical to managing recurrence and ensuring patient safety. Thyroglobulin levels serve as an effective biomarker for early detection of any residual disease, guiding follow-up care. This patient's initial level of thyroglobulin was 15.2 ng/mL. This was obtained post initial cystectomy but prior to thyroidectomy. Thyroglobulin monitoring and follow-up are essential for early detection and management of recurrence. This is particularly true for well-differentiated thyroid cancers, which this is not. However, it can still be an important indicator for the presence of thyroid tissue in other areas which could point to a recurrent malignancy. This case emphasizes the need for a tailored approach in managing struma ovarii, considering the variability in malignant transformation risk.